# File lib/generators/devise_token_auth/install_generator.rb, line 74
    def add_route_mount
      f    = "config/routes.rb"
      str  = "mount_devise_token_auth_for '#{user_class}', at: '#{mount_path}'"

      if File.exist?(File.join(destination_root, f))
        line = parse_file_for_line(f, "mount_devise_token_auth_for")

        unless line
          line = "Rails.application.routes.draw do"
          existing_user_class = false
        else
          existing_user_class = true
        end

        if parse_file_for_line(f, str)
          say_status("skipped", "Routes already exist for #{user_class} at #{mount_path}")
        else
          insert_after_line(f, line, str)

          if existing_user_class
            scoped_routes = ""+
              "as :#{user_class.underscore} do\n"+
              "    # Define routes for #{user_class} within this block.\n"+
              "  end\n"
            insert_after_line(f, str, scoped_routes)
          end
        end
      else
        say_status("skipped", "config/routes.rb not found. Add \"mount_devise_token_auth_for '#{user_class}', at: '#{mount_path}'\" to your routes file.")
      end
    end