Created tests for Puppy/PuppyRepo post database integration.

Puppy_spec tests for an initialized instance of the class.
PuppyRepo_spec tests for 1. adding a puppy to the database 2. finding a puppy in the database by the breed_id.
Note* it is important that the puppy_object, although input without a breed_id, returns an object with breed_id because the the Breed table's id (breed_id) is the foreign key for Puppy table.