// POST api/games
 public Guid Post(Game game)
 {
     game.Id = Guid.NewGuid();
     game.StartedAt = DateTime.Now;
     game.Users = new List<User>();
     games.Add(game);
     return game.Id;
 }
        // PUT api/games
        public void Put(Game game)
        {
            Game originalGame = games.Find(m => m.Id == game.Id);
            if (originalGame != null)
            {
                originalGame.Finished = true;
                originalGame.FinishedAt = game.FinishedAt;
            }

        }