Your TurnTracker class must implement the following methods:
• addPlayer(player)
o adds a player to the turn tracker after the last player that was added
to the tracker (i.e., this player should be added directly after the
_tail node and then become the new _tail)
• nextPlayer()
o returns the next player in the turn order based on the current game
state
o if called when there are no players in the turn tracker, should raise
a RuntimeError
• numberOfPlayers()
o returns the number of players in the turn tracker
• skipNextPlayer()
o causes the next player in the turn order to be skipped
• reverseTurnOrder()
o reverses the current direction of the turn order