GetLeaderboard returns all the users ordered in descending order of level, and for users on the same level, in the ascending order of last submission time.

GetRank fetches the rank of a user from the in-memory leaderboard @Summary returns the rank of the user who made the request.

HandleNextQuestion handles any request made to the /api/question/ endpoint @Summary returns the question for the level the user is on.

HandleSubmission handles answer attempts @Summary takes a post request with the answer attempt.

HeartBeat sends a response back, just to check if the server is up.