RFC: promotion coupon
We have the module sale_promotion that apply promotion to everyone based on some criteria. But a common practice to give promotion to customer is by given coupon [1].
So I think we could extend the sale_promotion to manage optionally coupon on them. In such case, the promotion will only be applied if the sale has the right coupon linked to it (and if other criteria match).
There are different kind of coupons, here is the list of common one that we could support by default:
- always valid
- with unique usage
- with unique usage per customer
[1] https://en.wikipedia.org/wiki/Coupon