        Register the given remote as TopGit-controlled. This will create
        the namespace for the remote branch bases and teach ``git fetch``
        to operate on them. However, from TopGit 0.8 onwards you need to
        use ``tg push``, or ``git push --mirror``, for pushing
        TopGit-controlled branches.

        ``tg remote`` takes an optional remote name argument, and an
        optional ``--populate`` switch.  Use ``--populate`` for your
        origin-style remotes: it will seed the local topic branch system
        based on the remote topic branches.  ``--populate`` will also make
        ``tg remote`` automatically fetch the remote, and ``tg update`` look
        at branches of this remote for updates by default.

        Using ``--populate`` with a remote name causes the ``topgit.remote``
        git configuration variable to be set to the given remote name.

