Create products table in db
Create product model and update table
  - added Amazon Id to product table in database
  - created relationship between images table and product table
validate for uniqueness on amzn_id for product so that product isn't saved mutliple times
Tested product model for validations and associations
  -discovered incorrect naming of images migration and corrected
  -corrected presence_of spelling error in validation
Merge pull request #3 from ShopIt2Me/model_product

Model product