MAPG-240 UserInChallengeRepository::isUserParticipatingInChallenge should return bool

src/Repository/UserInChallengeRepository.php

@@ -76,6 +76,6 @@ class UserInChallengeRepository
         $select->where('user_id', '=', $userId);
         $select->where('challenge_id', '=', $challenge->getId());
 
-        return $select->count();
+        return $select->count() != 0;
     }
 }