How to use concerns in Rails 4

Question

The default Rails 4 project generator now creates the directory \"concerns\" under controllers and models. I have found some explanations about how to use routing concerns,

Answer 1

In concerns make file filename.rb

For example I want in my application where attribute create_by exist update there value by 1, and 0 for updated_by

module TestConcern 
  extend ActiveSupport::Concern

  def checkattributes   
    if self.has_attribute?(:created_by)
      self.update_attributes(created_by: 1)
    end
    if self.has_attribute?(:updated_by)
      self.update_attributes(updated_by: 0)
    end
  end

end

If you want to pass arguments in action

included do
   before_action only: [:create] do
     blaablaa(options)
   end
end

after that include in your model like this:

class Role < ActiveRecord::Base
  include TestConcern
end