Scaffold and Migrations

After adding Migrations to my Rails app (they seem terrifc) when I run,
say,

ruby script/generate scaffold City

I am getting a dependency model error “Another migration is already
named
add_cities: db/migrate/001_add_cities.rb”

Model City is already in my app and when I run this scaffold generator
I’m
not intending to be touching any of the migration stuff.

What causing this error and what’s the fix? Thanks.

Brian