Adding models, migrations and controllers. Updated routes.

Added models/controllers for the labradors that are being bred, the
litters (upcoming, current and past), the puppies and the puppy
parents.

Need to add seed data for the tables to work with since adding/editing
them are not the main priority but rather display the information in
them is.

Need to work on updating the model relationships and displaying the
information correctly in the new views. Must link to pages from the
homepage.