This looks great. I wrote something similar last year (almost identical directory layout) but it wasn't anywhere near as clever; each database object directory

This looks great. I wrote something similar last year (almost identical directory layout) but it wasn't anywhere near as clever; each database object directory had an `up.sql` and `down.sql` file and depending on the 'mode' in which the script was invoked (up, down or refresh - which was down then up) ran the SQL scripts in order.