title: Make Devise raise ActiveRecord exceptions in registrations controller
body: <p>I'm trying to implement the devise registrations controller to accept AJAX logins with minimum use of overriding it. Currently it looks like this:</p>
  
  <pre><code>class RegistrationsController &lt; Devise::RegistrationsController
    clear_respond_to
    respond_to :json
    before_filter :configure_permitted_parameters
  
    protected
  
    def update_resource(resource, params)
      resource.update_without_password(params)
    end
  
    def configure_permitted_parameters
      devise_parameter_sanitizer.for(:sign_up).push(:name, :location)
      devise_parameter_sanitizer.for(:account_update).push(:name, :location, :soundcloud, :youtube, :twitter, :bandcamp)
    end
  
  end
  </code></pre>
  
  <p>The problem is, in Devise's registration controller, the create / update methods are called without the <code>!</code> (e.g. just <code>resource.save</code>)</p>
  
  <p>This is not ideal as validation errors like duplicate names, email addresses are not caught and instead I get an unhelpful 422 Unprocessable Entity error.</p>
  
  <p>Is their a configuation option or other easy way to make devise raise errors without having to overide the entire controller?</p>