Current updates the branch on the remote repository that shares a name with the current working branch.
git config push.default current
Simple pushes to the upstream branch, but will not work if the upstream branch is called something else.
git config push.default simple
Upstream pushes to the upstream branch, no matter what it is called.
git config push.default upstream
Matching pushes all branches that match on the local and the remote git config push.default upstream
After you've set the preferred style, use
git push
to update the remote repository.