Disable Cross Rails 4

disable_cross_rails_4.txt

step 1
Install rack-cors
into Gemfile define
gem 'rack-cors', :require => 'rack/cors'

Step 2

into Config.ru add the following lines

require 'rack/cors'
use Rack::Cors do
  # allow all origins in development
  allow do
    origins '*'
    resource '*', 
        :headers => :any, 
        :methods => [:get, :post, :delete, :put, :options]
  end
end