protected function post(\Club\BookingBundle\Entity\Field $field, $fl)
 {
     $em = $this->getDoctrine()->getManager();
     $field->setFieldLayout($fl);
     $em->persist($field);
     $intervals = $em->getRepository('ClubBookingBundle:Interval')->findBy(array('valid_to' => null, 'field' => $field->getId()));
     foreach ($intervals as $interval) {
         $interval->setValidTo(new \DateTime());
         $em->persist($interval);
     }
 }