It's worth noting that if you had real data, this migration is a Bad Idea. Here's why:

* You add `shipping_address_id` to the `payments` table
* You remove the `payment_id` from `shipping_addresses` table  - now you don't know which payments were associated with which shipping address.
* Presumably, you want the `shipping_address_id` on `payments` to be the inverse of the `payment_id` on `shipping_addresses`, but now your existing data doesn't have that connection between the two tables at all.

In this case, you'd write some SQL to grab `payment_id` and `id` from each `shipping_address` record and associate the two records in `payments`.