Level: Adding a fork after cloning upstream

[benthayer]

Sometimes people clone before they fork, or they fork, but then clone the upstream repository.

When they do this, they need to add their fork as a remote.

They might use git remote set-url origin mygit and git remote add upstream upstreamurl. They may also do git remote rename origin upstream and git remote add origin mygit.

We should have a level to help them handle this situation.