Cancan with rails_admin

Question

class Ability
  include CanCan::Ability

  def initialize(user)
       user ||= User.new 

         if user and user.admin?
           can :access, :rails_admin
           can :dashboard
            if user.has_role? :superadmin       
               can :manage, :all
             elsif user.has_role? :admin
               can :manage, [Event]

             end   
         end 
        end

即使我指定了can：manage，：all / can：access，：rails_admin can：dashboard并删除所有内容 - 它仍然指示我访问拒绝访问错误的主页。这是我的应用程序控制器。

class ApplicationController < ActionController::Base

 rescue_from CanCan::AccessDenied do |exception|
    redirect_to '/', notice: 'Access Denied'
  end 
 end

这里发生了什么？！