Update WhiteCard factory to subclass Card factory.
Update Card model with CARD_TYPES, and type validation.

CARD::CARD_TYPES will contain the types a Card is allowed to have.

Card.type must be present when the record is saved and cannot be
changed after the fact.
Add Card specifications.
Add validations on #draw, #pick to WhiteCard model.

WhiteCards should never have a #draw or #pick value and will throw
and error if a non-nil value for those columns are attempted to be
saved to the db.
Add WhiteCard specifications.