/**
  * Finds all field values associated with the $signup
  * 
  * @param \Activity\Model\ActivitySignup $signup
  * @return array of \Activity\Model\ActivityFieldValue
  */
 public function getFieldValuesBySignup(\Activity\Model\ActivitySignup $signup)
 {
     return $this->getRepository()->findBy(array('signup' => $signup->getId()));
 }