title: How to get library of devise so that it can be modified like php libraries
body: <p>Getting the generated devise controller like.</p>
  
  <pre><code>class Users::SessionsController &lt; Devise::SessionsController
     before_action :configure_sign_in_params, only: [:create]
  
    # GET /resource/sign_in
     def new
      # super
          #       byebug
          redirect_to  root_url   
     end
  
    # POST /resource/sign_in
     def create
          puts 'Login user............'        
          super
          puts '..............'
  
     end
  
    # DELETE /resource/sign_out
     def destroy
       super
     end
  
    # protected
  
    # If you have extra params to permit, append them to the sanitizer.
     def configure_sign_in_params
       devise_parameter_sanitizer.permit(:sign_in, keys: [:attribute])
     end
  end
  </code></pre>
  
  <p>where can I get the library of devise so that I can modify it new function and do not get error of double redirect.</p>
  
  <p>suppose in terminal logs out put is as Processing by </p>
  
  <pre><code>Users::SessionsController#new as HTML
  </code></pre>
  
  <p>where is the code written for method new in its devise library.</p>