added migration for rewritten models

Player gets the score as a foreign key
Player has a custom save method, which updates the player score
added the Game model
Merge branch 'add-game-model'

Conflicts:
	scorekeeper/admin.py
	scorekeeper/models.py
	scorekeeper/tests.py
Merge branch 'rewrite-scorekeeper-models'

Conflicts:
	scorekeeper/models.py
	scorekeeper/tests.py