Could we have a --fake option on migrate:up migrate:down?

[kitsunde]

I'll sometimes need to manually intervene into the database migration and manually apply things, especially in dev. Naturally on hitting the appropriate migration it'll fail, because I've perform it manually.

This isn't such a big issue now because of what I raised in #931 where it'll mark failed migrations as completed, but if I was able to argue that they should hard-fail this would be a necessary remedy to continuing the migrations.

[kitsunde]

Sorry posted this to the wrong repo, meant to go to: propelorm/Propel2#834