Using devise + activeadmin with one User model and separate sign_in entry points

active_admin.rb

  config.authentication_method = :authenticate_admin_user!
  config.current_user_method = :current_admin_user
  config.logout_link_path = :destroy_user_session_path

admin_user.rb

class AdminUser < User
  self.inheritance_column = :_type_disabled
end

application_controller.rb

  def authenticate_admin_user!
    if current_admin_user.present? and current_user.blank?
      sign_in current_admin_user, bypass: true
    end

    super
  end

routes.rb

  devise_for :users
  devise_for :admin_users, ActiveAdmin::Devise.config
  ActiveAdmin.routes(self)

Thanks!!!