InitLiveLeaderboard initializes the channels and starts the goroutine that maintains the in-memory leaderboard.

FetchRank is used to fetch the rank of a user from the in-memory leaderboard.

NewUser is used to add a new user to the in-memory leaderboard.

ReturnRank is used to return the fetched rank back to the main routine.

UpdateUser is used to update the in-memory leaderboard.