added bid migration and model
* added validations to model
* corrected field naming in auction to snail_case
added create and update to bid controller
* fixed wrong named var in auctions controller
Merge branch 'bids' into make-a-bid

Conflicts:
	app/models/auction.rb
	config/routes.rb
	db/schema.rb
Removed unused and dublicated migration

If you have a problem with the migration, rollback and do it again