added PurchasedItem Model and Test
added PurchasedItemRepository
updated Purchase Items
Merge branch 'master' of https://github.com/gilz688/POSS

Conflicts:
	app/models/ItemRepository.php
	app/models/UserRepository.php
	app/tests/acceptance/AuthenticationCest.php
	app/tests/unit/ItemTest.php
	app/tests/unit/UserTest.php