IT Knowledge Sharing: Rails Getting Started

+Install Ruby (gem update rails)
+Install Rails (gem install rails)
+Install sqlite  (download precompiled binaries for windows sqlite-shell-win32-x86-version.zip)
+Make your application
    rails new path/to/your/new/application
    cd path/to/your/new/application
    bin/rails server
    You're running Rub on Rails! Follow the instructions on http://localhost:3000
+To check ruby version
    ruby -v
+To check rails version
    rails -v
+Installign sqlite3
    gem install sqlite3
+To check sqlite version
    sqlite3 --version
+create sqlite database
    sqlite dbname.db
    .help to display help files
    .quit to exit sqlite
+create controller
    cd bin
    rails generate controller welcome index
    (the above command will create controller, view and add route for welcome controller with index method)
+rails' route
    get 'welcome/index'
    root 'welcome#index'
    (this will map http://localhost:3000/welcome/index to welcome#index (index method of welcome controller)
+To create resource (RESTful actions)
    add the below line to routes.rb
    resources :articles
    use bin/rake routes to view all defined routes for all the standard RESTful actions.
    You can create, read, update and destroy items for a resource and these operations are reffered to as CRUD operations.

   
    rails generate controller articles
    (Note: There are public, private and protected methods in Ruby, but only public methods can be actions for controllers.)+Creating the Model
    Models in Rails use a singular name, and their corresponding database tables use a plural name.

    rails generate model Article title:string text:text

    Rails responded by creating a bunch of files.

+Running a migration
    rake db:migrate
If you would like to execute migrations in another environment, for instance in production, you must explicitly pass it when invoking the command: bin/rake db:migrate RAILS_ENV=production.

+Saving data in the controller

    def create
        @article = Article.new(parames[:article])
        @article.save
        redirect_to @article
    end

The destroy method is generally the last CRUD action in the controller, and like the other public CRUD actions, it must be placed before any private or protected methods.
    index, show, new, edit, create, update, destroy
In general, Rails encourages using resources objects instead of declaring routes manually.

+Creating a related model
    rails generate model Comment commenter:string body:text article:references

+Associating Models
    class Article < ActiveRecord::Base
        has_many :comments
        validates :title, presence: true, length: {minimum: 5}
    end

+Creating a nested resource withing articles
    resources :articles do
        resources :comments
    end
   
+Deleting Associated Objects
    class Article < ActiveRecord::Base
        has_many :comments, dependent: :destroy
        validates :title, presence: true, length: { minimum: 5 }
    end
   
+Rails Guides
    rake doc:guides
+Rails API documentation
    rake doc:rails

To be able to generate the Rails Guides locally with the doc:guides rake task you need to install the RedCloth and Nokogiri gems. Add it to your Gemfile and run bundle install and you're ready to go.