Replace the nullable PlayerConnectionIds array with a private List<Player> inside Game and add AddPlayer/RemovePlayer methods to manage membership. Have GameRepository.Create attach the initial player to the newly created game. Implement GameManager.CreateGame and JoinGame to call the repository (using the injected gameRepository) — CreateGame returns the created game's code and JoinGame looks up the game and tries to add the player. Also update imports accordingly. These changes centralize player handling in the Game model and connect repository/manager flows to use it.