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			262 lines
		
	
	
		
			9.0 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
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								== Welcome to Rails
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								Rails is a web-application framework that includes everything needed to create
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								database-backed web applications according to the Model-View-Control pattern.
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								This pattern splits the view (also called the presentation) into "dumb"
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								templates that are primarily responsible for inserting pre-built data in between
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								HTML tags. The model contains the "smart" domain objects (such as Account,
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								Product, Person, Post) that holds all the business logic and knows how to
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								persist themselves to a database. The controller handles the incoming requests
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								(such as Save New Account, Update Product, Show Post) by manipulating the model
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								and directing data to the view.
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								In Rails, the model is handled by what's called an object-relational mapping
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								layer entitled Active Record. This layer allows you to present the data from
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								database rows as objects and embellish these data objects with business logic
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								methods. You can read more about Active Record in
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								link:files/vendor/rails/activerecord/README.html.
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								The controller and view are handled by the Action Pack, which handles both
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								layers by its two parts: Action View and Action Controller. These two layers
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								are bundled in a single package due to their heavy interdependence. This is
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								unlike the relationship between the Active Record and Action Pack that is much
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								more separate. Each of these packages can be used independently outside of
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								Rails. You can read more about Action Pack in
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								link:files/vendor/rails/actionpack/README.html.
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								== Getting Started
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								1. At the command prompt, create a new Rails application:
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								       <tt>rails new myapp</tt> (where <tt>myapp</tt> is the application name)
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								2. Change directory to <tt>myapp</tt> and start the web server:
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								       <tt>cd myapp; rails server</tt> (run with --help for options)
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								3. Go to http://localhost:3000/ and you'll see:
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								       "Welcome aboard: You're riding Ruby on Rails!"
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								4. Follow the guidelines to start developing your application. You can find
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								the following resources handy:
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								* The Getting Started Guide: http://guides.rubyonrails.org/getting_started.html
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								* Ruby on Rails Tutorial Book: http://www.railstutorial.org/
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								== Debugging Rails
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								Sometimes your application goes wrong. Fortunately there are a lot of tools that
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								will help you debug it and get it back on the rails.
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								First area to check is the application log files. Have "tail -f" commands
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								running on the server.log and development.log. Rails will automatically display
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								debugging and runtime information to these files. Debugging info will also be
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								shown in the browser on requests from 127.0.0.1.
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								You can also log your own messages directly into the log file from your code
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								using the Ruby logger class from inside your controllers. Example:
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								  class WeblogController < ActionController::Base
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								    def destroy
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								      @weblog = Weblog.find(params[:id])
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								      @weblog.destroy
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								      logger.info("#{Time.now} Destroyed Weblog ID ##{@weblog.id}!")
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								    end
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								  end
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								The result will be a message in your log file along the lines of:
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								  Mon Oct 08 14:22:29 +1000 2007 Destroyed Weblog ID #1!
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								More information on how to use the logger is at http://www.ruby-doc.org/core/
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								Also, Ruby documentation can be found at http://www.ruby-lang.org/. There are
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								several books available online as well:
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								* Programming Ruby: http://www.ruby-doc.org/docs/ProgrammingRuby/ (Pickaxe)
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								* Learn to Program: http://pine.fm/LearnToProgram/ (a beginners guide)
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								These two books will bring you up to speed on the Ruby language and also on
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								programming in general.
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								== Debugger
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								Debugger support is available through the debugger command when you start your
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								Mongrel or WEBrick server with --debugger. This means that you can break out of
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								execution at any point in the code, investigate and change the model, and then,
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								resume execution! You need to install ruby-debug to run the server in debugging
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								mode. With gems, use <tt>sudo gem install ruby-debug</tt>. Example:
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								  class WeblogController < ActionController::Base
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								    def index
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								      @posts = Post.all
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								      debugger
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								    end
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								  end
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								So the controller will accept the action, run the first line, then present you
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								with a IRB prompt in the server window. Here you can do things like:
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								  >> @posts.inspect
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								  => "[#<Post:0x14a6be8
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								          @attributes={"title"=>nil, "body"=>nil, "id"=>"1"}>,
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								       #<Post:0x14a6620
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								          @attributes={"title"=>"Rails", "body"=>"Only ten..", "id"=>"2"}>]"
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								  >> @posts.first.title = "hello from a debugger"
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								  => "hello from a debugger"
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								...and even better, you can examine how your runtime objects actually work:
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								  >> f = @posts.first
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								  => #<Post:0x13630c4 @attributes={"title"=>nil, "body"=>nil, "id"=>"1"}>
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								  >> f.
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								  Display all 152 possibilities? (y or n)
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								Finally, when you're ready to resume execution, you can enter "cont".
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								== Console
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								The console is a Ruby shell, which allows you to interact with your
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								application's domain model. Here you'll have all parts of the application
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								configured, just like it is when the application is running. You can inspect
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								domain models, change values, and save to the database. Starting the script
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								without arguments will launch it in the development environment.
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								To start the console, run <tt>rails console</tt> from the application
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								directory.
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								Options:
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								* Passing the <tt>-s, --sandbox</tt> argument will rollback any modifications
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								  made to the database.
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								* Passing an environment name as an argument will load the corresponding
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								  environment. Example: <tt>rails console production</tt>.
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								To reload your controllers and models after launching the console run
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								<tt>reload!</tt>
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								More information about irb can be found at:
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								link:http://www.rubycentral.org/pickaxe/irb.html
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								== dbconsole
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								You can go to the command line of your database directly through <tt>rails
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								dbconsole</tt>. You would be connected to the database with the credentials
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								defined in database.yml. Starting the script without arguments will connect you
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								to the development database. Passing an argument will connect you to a different
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								database, like <tt>rails dbconsole production</tt>. Currently works for MySQL,
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								PostgreSQL and SQLite 3.
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								== Description of Contents
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								The default directory structure of a generated Ruby on Rails application:
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								  |-- app
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								  |   |-- assets
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								  |   |   |-- images
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								  |   |   |-- javascripts
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								  |   |   `-- stylesheets
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								  |   |-- controllers
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								  |   |-- helpers
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								  |   |-- mailers
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								  |   |-- models
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								  |   `-- views
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								  |       `-- layouts
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								  |-- config
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								  |   |-- environments
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								  |   |-- initializers
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								  |   `-- locales
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								  |-- db
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								  |-- doc
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								  |-- lib
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								  |   |-- assets
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								  |   `-- tasks
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								  |-- log
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								  |-- public
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								  |-- script
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								  |-- test
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								  |   |-- fixtures
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								  |   |-- functional
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								  |   |-- integration
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								  |   |-- performance
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								  |   `-- unit
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								  |-- tmp
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								  |   `-- cache
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								  |       `-- assets
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								  `-- vendor
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								      |-- assets
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								      |   |-- javascripts
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								      |   `-- stylesheets
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								      `-- plugins
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								app
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								  Holds all the code that's specific to this particular application.
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								app/assets
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								  Contains subdirectories for images, stylesheets, and JavaScript files.
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								app/controllers
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								  Holds controllers that should be named like weblogs_controller.rb for
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								  automated URL mapping. All controllers should descend from
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								  ApplicationController which itself descends from ActionController::Base.
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								app/models
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								  Holds models that should be named like post.rb. Models descend from
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								  ActiveRecord::Base by default.
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								app/views
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								  Holds the template files for the view that should be named like
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								  weblogs/index.html.erb for the WeblogsController#index action. All views use
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								  eRuby syntax by default.
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								app/views/layouts
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								  Holds the template files for layouts to be used with views. This models the
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								  common header/footer method of wrapping views. In your views, define a layout
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								  using the <tt>layout :default</tt> and create a file named default.html.erb.
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								  Inside default.html.erb, call <% yield %> to render the view using this
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								  layout.
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								app/helpers
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								  Holds view helpers that should be named like weblogs_helper.rb. These are
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								  generated for you automatically when using generators for controllers.
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								  Helpers can be used to wrap functionality for your views into methods.
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								config
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								  Configuration files for the Rails environment, the routing map, the database,
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								  and other dependencies.
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								db
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								  Contains the database schema in schema.rb. db/migrate contains all the
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								  sequence of Migrations for your schema.
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								doc
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								  This directory is where your application documentation will be stored when
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								  generated using <tt>rake doc:app</tt>
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								lib
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								  Application specific libraries. Basically, any kind of custom code that
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								  doesn't belong under controllers, models, or helpers. This directory is in
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								  the load path.
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								public
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								  The directory available for the web server. Also contains the dispatchers and the
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								  default HTML files. This should be set as the DOCUMENT_ROOT of your web
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								  server.
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								script
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								  Helper scripts for automation and generation.
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								test
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								  Unit and functional tests along with fixtures. When using the rails generate
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								  command, template test files will be generated for you and placed in this
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								  directory.
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								vendor
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								  External libraries that the application depends on. Also includes the plugins
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								  subdirectory. If the app has frozen rails, those gems also go here, under
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								  vendor/rails/. This directory is in the load path.
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