Regenerate Fixture file

so lets say you create a model and you edit your migrations
but something changes and its like very really in your project so you
just edit the migration file and
roll back to version=0 and recreate all the tables

is there a way to re-generate like script/generate fixture tablename
i don't want to replace the model file just recreate fixture file
based on shema.rb
is there a way to do that