git remote remove origin
git remote add origin [BASE-GIT-REPO]
git remote set-url --add --push origin [BASE-GIT-REPO]
git remote set-url --add --push origin [SECONDARY-GIT-REPO]
$ git remote -v
origin [BASE-GIT-REPO] (fetch)
origin [BASE-GIT-REPO] (push)
origin [SECONDARY-GIT-REPO] (push)