public IEnumerable <ChallengeDTO> GetChallengesByUser(int userId)
{
var repo = new ChallengeRepository();
var challengeIds = repo.GetChallengeIdsByUser(userId);
var myChallenges = new List <ChallengeDTO>();
foreach (var challengeId in challengeIds)
{
var challenge = repo.GetChallege(challengeId);
myChallenges.Add(challenge);
}
return(myChallenges);
}