app/controllers/application_controller.rb

@@ -2,6 +2,12 @@ class ApplicationController < ActionController::Base

                   protect_from_forgery
              

                 
              

                   before_filter :authenticate_user!
              

                +  before_action :configure_permitted_parameters, if: :devise_controller?
              

                 
              

                   helper :all
              

                +
              

                +  protected
              

                +  def configure_permitted_parameters
              

                +    devise_parameter_sanitizer.for(:sign_up) << [:username, :email, :invitation_code]
              

                +  end
              

                 end