private void CmdAddGroup(IPlayer player, string cmd, string[] args)
        {
            if (args.Length != 3)
            {
                player.Reply(GetMessage("Syntax : addgroup", player.Id));
                return;
            }

            IPlayer  target = FindPlayer(args[0], player);
            TimeSpan duration;

            if (target == null)
            {
                return;
            }

            if (!TryParseTimeSpan(args[2], out duration))
            {
                player.Reply(GetMessage("Invalid Time Format", player.Id));
                return;
            }

            PlayerInformation.GetOrCreate(target).AddGroup(args[1], DateTime.UtcNow + duration);
        }