anchor.diff:  -module(bc_game_model).
   -include("bc_model.hrl").
   
  --export(win_game/2, update_state/2).
  +-export(save/1, 
  +		win_game/2, 
  +		update_state/2).
   
  +-spec save(Privacy :: integer()) -> {ok, GameId :: integer()} | 
  +									{error, Reason :: string()}.
   save(Privacy) ->
   	Now = now(),
   	GameId = bc_model:gen_id(game),
  
positive.code: 			{error, Reason}
  	end.
  
  update_state(GameId, GameState) ->
  	case mnesia:sync_transaction(fun() -> 
  										 [Game] = mnesia:wread(game, GameId), 
  
negative.code: 			{error, Reason}
  	end.
  
  -spec win(GameId :: integer(), 
  		  WinnerId :: integer()) -> {ok, won} | {error, Reason :: string()}.
  win(GameId, WinnerId) ->
  	case mnesia:sync_transaction(fun() -> 
  									[Game] = mnesia:wread(game, GameId),
  