Implemented utilization of PostgreSQL database in breed/breed_repo.

From previously utilizing a hash instance of breed_repo class, refactored breed_repo to speak SQL to the database.
Breed class now only initializes an instance with name and price. All other responsibilities, including getting and pushing data has been given to breed_repo class.
Breed_repo class inherits from the Repo class and its @db, which is our PG connection to puppy-breeder-db.
Added functionality: 1. create a breed table 2. drop the breed table 3.  add to breed table 4. retrieve data from breed table 5. 'prettify' the result we get from the database into an instance of the breed class for other classes to use.
Passed all tests in breed_spec/breed_repo_spec.