private void button3_Click(object sender, EventArgs e)
{
WaitingRoom.AssignPlayersToGames();
var context = GlobalHost.ConnectionManager.GetHubContext <ServerHub>();
foreach (string connID in Program.PlayingGames.SelectMany(playingGame => playingGame.playersID))
{
context.Clients.Client(connID).StartGameMsg("start");
}
}