ruby on rails - How do I use Devise and ActiveAdmin for the same User model? -

i have activeadmin , devise working users. use devise log in regular non-admin users same user model. how can this? (i want have admin flag in user model admins.) tried adding 2nd line routes.rb

devise_for :users, activeadmin::devise.config devise_for :users 

but gave error when tried list routes

>rake routes dl deprecated, please use fiddle rake aborted! argumenterror: invalid route name, in use: 'new_user_session' may have defined 2 routes same name using `:as` option, or may overriding route defined resource same naming. latter, can restrict routes created `resources` explained here: http://guides.rubyonrails.org/routing.html#restricting-the-routes-created 

i've created authorization adapter checks user.admin == true , working ok activeadmin. https://github.com/activeadmin/activeadmin/blob/master/docs/13-authorization-adapter.md

i found http://dan.doezema.com/2012/02/how-to-implement-a-single-user-model-with-rails-activeadmin-and-devise/

but ended doing this

devise 3.4.1
activeadmin 1.0.0.pre1
rails 4.2.1

routes.rb

  devise_for :admin_users, {class_name: 'user'}.merge(activeadmin::devise.config)   activeadmin.routes(self)    devise_for :users   resources :users 

application_controller.rb

  def access_denied(exception)     redirect_to root_path, alert: exception.message   end 

config/initializers/active_admin.rb

config.authorization_adapter = activeadminadapter config.on_unauthorized_access = :access_denied 

(and changing methods _user admin_user.)

app/models/active_admin_adapter.rb

class activeadminadapter < activeadmin::authorizationadapter   def authorized?(action, subject = nil)     user.admin == true   end end 

and

rails generate migration add_admin_to_users admin:boolean