Devise before filter that prevents access to “new_user_registration_path” unless user is signed-in

registrations_controller.rb

#/ app / controllers / registrations_controller.rb
class RegistrationsController < Devise::RegistrationsController
  before_filter :authenticate_user!
end

routes.rb

#/ config / routes.rb
devise_for :users, :controllers => { :registrations => 'registrations'}