There doesn't seem to be support for unique constraints passed to the changeColumn() function for the Postgres backend; they just get ignored. I added support for it. Please pull this change into your repo.
added handling for unique constraints when changing a column on postg…
Any chance you'd be willing to add a test for that so it doesn't slip through the cracks again in the future? If not, I can write one, but I might not get to it right away.
I can probably figure out how to do that. I'll try to get to it today.
Fix is in version 0.2.4