组控制器类图

ActionController::Base

+ before_action()+ include()

GroupsController

+ users : User+ groups : Group

+ show()+ new()+ edit()+ index()+ destroy()+ create()+ update()- group_params()- admin_user?()

ApplicationController

+ logged_in_user()- logged_in?()

SessionsHelper

+ log_in(User: user)+ current_user()+ logged_in?()+ forget(User: user)+ log_out()+ remember(User: user)+ current_user?(User: user)+ redirect_back_or(String: url)+ store_location()