Join Game endpoint - Githubissues

One a game is created, it is in Lobby(LobbyModel) mode. Players need to be able to join games.

[ ] in shared/src.. make a join_game module, with a Request and Response.
[ ] Request should take a game_id and a player_name.
[ ] Response should contain a list of the names of the players in the game so far.
This should involve a get_players function on Game, which returns host + opponents.
[ ] Make an endpoint for joining a game.
[ ] The server needs to look for that game and add that player to that game,
[ ] Include error cases, and make the response fail appropriately.

Chadtech / FIGHT-LINES-DEPR-