code: public function loginAction(Request $request, Application $app)
      {
          $options = array(
              "is_ajax" => $request->isXmlHttpRequest(),
              "error" => $app['security.last_error']($request),
              "last_username" => $app['session']->get('_security.last_username'),
              "template_assets" => $app["red_kite_cms.template_assets"],
              "twig" => $app["twig"],
              "red_kite_cms_config" => $app["red_kite_cms.configuration_handler"],
              "assets" => array(
                  'getExternalStylesheets' => array(
                      $app["red_kite_cms.configuration_handler"]->webDir(
                      ) . '/components/redkitecms/twitter-bootstrap/css/bootstrap.min.css',
                      $app["red_kite_cms.configuration_handler"]->webDir() . '/sb-admin-2/css/sb-admin-2.css',
                  ),
              ),
          );
  
          return parent::login($options);
      }
docs: Login action
  
  @param \Symfony\Component\HttpFoundation\Request $request
  @param \Silex\Application                        $app
  @return \Symfony\Component\HttpFoundation\Response