[Rails] "rake migrate" runs old migration

[Ingo Weiss]

Hi,

I created a new migration with "script/generate migration", but when I
try to run it with "rake migrate" it looks like the old migration runs
again (which generates an error since it tries to create a table that's
there).

How does Rails figure out which migration to run? Can I explicitly run a
specific migration to work around the problem? What might have caused it
in the first place?

This happened after I upgraded to Rails 1.1 so I am wondering whether
this could have something to do with it.

Thanks for any help!
Ingo W.