Field created_by added in ChallengeHostTeam model. (#85)
Field created_by added in ChallengeHostTeam model. (#85)

One very specific use case for this alter is to fetch
ChallengeHostTeam of a specifi user.
taranjeet/EvalAI,taranjeet/EvalAI,taranjeet/EvalAI,taranjeet/EvalAI