public class RosterTransaction : RosterInteraction
    {
        public Roster AddPlayer(Roster roster, Player player)
	{
	    return roster.players.Add(player);
	}

	public Roster DropPlayer(Roster roster, Player playerToDrop)
	{
            return roster.players.Where (player => player.id != playerToDrop.id);
	}

	public void ProjectedPoints(Roster roster)
	{

	}

	public void Injuries(Roster roster)
	{

	}

}