为什么此devise_group调用会出现NoMethodError？

我正在使用devise 3.5.2，ruby 2.2.2，rails 4.2.3

I'm using devise 3.5.2, ruby 2.2.2, rails 4.2.3

class ApplicationController < ActionController::Base
  # Prevent CSRF attacks by raising an exception.
  protect_from_forgery with: :exception

  devise_group :user, contains: [:manager, :employee]
end

我的理解是Devise应该加载这些帮助程序自动完成，我应该能够在ApplicationController中使用它们而无需做任何特殊的事情。

My understanding is that Devise should load these helpers automatically and I should be able to use them in ApplicationController without doing anything special.

我尝试运行带有 rails s的应用程序，我得到此错误：

I try and run the app with 'rails s' and I get this error:

multi-user-role-devise / app / controllers / application_controller.rb： 6：在
< class：ApplicationController>'中：未定义方法 devise_group'for
ApplicationController：Class（NoMethodError）from
/ home /me/ror-code/multi-user-role-devise/app/controllers/application_controller.rb:1:in
`'.... etc

multi-user-role-devise/app/controllers/application_controller.rb:6:in <class:ApplicationController>': undefined methoddevise_group' for ApplicationController:Class (NoMethodError) from /home/me/ror-code/multi-user-role-devise/app/controllers/application_controller.rb:1:in `' ....etc

我该如何解决？

Gemfile：

source 'https://rubygems.org'
ruby '2.2.2'
gem 'rails', '4.2.3'
gem 'sqlite3'
gem 'sass-rails', '~> 5.0'
gem 'uglifier', '>= 1.3.0'
gem 'coffee-rails', '~> 4.1.0'
gem 'jquery-rails'
gem 'turbolinks'
gem 'jbuilder', '~> 2.0'
gem 'foundation-rails'
gem 'simple_form'
gem 'devise'
group :development do
  gem 'better_errors'
  gem 'quiet_assets'
  gem 'rails_layout'
  gem 'spring-commands-rspec'
end
group :development, :test do
  gem 'factory_girl_rails'
  gem 'faker'
  gem 'rspec-rails'
  gem 'byebug'
  gem 'web-console', '~> 2.0'
  gem 'spring'
end
group :test do
  gem 'capybara'
  gem 'database_cleaner'
  gem 'launchy'
  gem 'selenium-webdriver'
end

管理器类：

class Manager < User
end

员工类别：

class Employee < User
end