This extension creates a DiscountCode resource. discount_code belongs_to :user order has_many :discount_codes
We also will add some columns to the Order model. order.discount_code_id order.discount_total => once the discount is calculated it is stored on the order order.commission_total => likewise
The methods added: order.discount_total order.commission_total order.total_with_discount order.total_without_discount
A user can become an affiliate by adding a discount_code