Use outside rubocop

[robbprescott]

I'd love to use this outside rubocop in another rake file but I couldn't figure out how.

The use case I have is that I'm working on a branch and have a few migrations. I want to rollback just the migrations on this branch so that I can edit them and remigrate them.

If we know the version, we can easily do this rake db:migrate:down VERSION=2018010100000. It seems like with lineup we could easily grab those versions and do something like rake db:rollback:local and just rollback the migrations from the current branch, without rolling back any migrations directly in master.