Home 3/21: Successful unit testing with mock

Yay! Followed the instructions at:
https://tutsplus.com/tutorial/better-testing-in-laravel/

I created a couple of additional classes:
  ItemRepositoryInterface
  EloquentItemRepository

Both of these will deal with items. I'm really not sure why the
EloquentItemRepository clas is needed, but it seems to be...

	modified:   api/app/controllers/ItemsController.php
	new file:   api/app/models/repositories/EloquentItemRepository.php
	new file:   api/app/models/repositories/ItemRepositoryInterface.php
	modified:   api/app/routes.php
	modified:   api/app/tests/TestCase.php
	modified:   api/app/tests/controllers/ItemsControllerTest.php