Create endpoint for new game

[jacobchrismarsh]

Gonna assume that @gaganza will send me JSON that looks like this:

{
   "user_id_1": str,
   "user_id_2": str,
   "white_user_id": str,
   "black_user_id": str,
   "id": int
}

And I will return JSON like this:

{
    "success": <boolean>
}