title: Creating a new admin user in activeadmin
body: <p>I'm using active admin on rails 4, I white-listed the parameters for admin users in the controller using:</p>
  
  <pre><code>ActiveAdmin.register AdminUser do
   controller do
    def permitted_params
     params.permit(:admin_user =&gt; [:email, :password, :password_confirmation])
    end
   end
  end
  </code></pre>
  
  <p>but when I try to add a new user, I get the error "cannot be blank" on the email and password fields. The logs read the following:</p>
  
  <pre><code>Unpermitted parameters: utf8, authenticity_token, commit
  Unpermitted parameters: utf8, authenticity_token, admin_user, commit
  </code></pre>
  
  <p>Is there something I'm missing?</p>