Easy way to opt out of dev loop for some migrations

[JAForbes]

Sometimes you want to mark as migration as stable locally and not re-run it every time.

Effectively get --prod behaviour but in --dev

This is essentially import for bulk updates / inserts that are chunked. You don't want to constantly re-run them when they take a while to execute.

Just a simple export to tell pgmg to mark it as done even if its in dev mode. And if you unmark the flag it should pick it up again on the next run. And if you mistakenly commit that flag enabled it should have no impact on --prod.