no-issue
* Removed NOT_NULL constraint from stripe_coupon_id
When handling disconnecting from Stripe - we remove all Stripe data from
our database to ensure we do not have bad/invalid data stored. Removing
this constraint will allow us to set the value to NULL.
* Added created_at column to offer_redemptions
Offer Redemptions are not just a joining table, but an event. A created_at
date allows them to be ordered
Because this is in alpha it is simpler to just drop the tables and
re-add them, due to offer_redemptions depending on offers, we also drop
this table and re-add it.