Demo reset indication

[kochen]

Every x amount of time the Demo resets without any notification/indication, resulting in an error:
Fatal error: Uncaught Symfony\Component\Debug\Exception\FatalThrowableError: Type error: Argument 1 passed to FOS\RestBundle\Controller\ExceptionController::__construct() must implement interface FOS\RestBundle\View\ViewHandlerInterface, none given, called in /app/var/cache/prod/classes.php on line 4218 in /app/vendor/friendsofsymfony/rest-bundle/Controller/ExceptionController.php:43 Stack trace: #0 /app/var/cache/prod/classes.php(4218): FOS\RestBundle\Controller\ExceptionController->__construct() #1 /app/var/cache/prod/classes.php(4908): Symfony\Component\HttpKernel\Controller\ControllerResolver->instantiateController('FOS\\RestBundle\\...') #2 /app/var/cache/prod/classes.php(4214): Symfony\Bundle\FrameworkBundle\Controller\ControllerResolver->instantiateController('FOS\\RestBundle\\...') #3 /app/var/cache/prod/classes.php(4901): Symfony\Component\HttpKernel\Controller\ControllerResolver->createController('FOS\\RestBundle\\...') #4 /app/var/cache/prod/classes.php(4155): Symfony\Bundle\FrameworkBundle\Controller\Controlle in /app/vendor/friendsofsymfony/rest-bundle/Controller/ExceptionController.php on line 43

It would be a good idea to put a timer or some other form of indication about when/that the demo is about to be reset.
and of course a nicer error_page would be nice.