Reviewing in progress work on Github

[Ian Booth]

One of the many things I miss now that we have moved to Github/git is the
ability to put up a merge proposal with in-progress work, allowing collaboration
on the implementation as it evolves etc. Launchpad supported this nicely, as it
didn't spam people with emails for wip mps etc.

I don't think Github supports this concept. Perhaps a way around it is to do a
pull request against one's forked copy of the main Juju repo. That way, people
can still easily see your work, but without the general spam. Sadly, it doesn't
allow the pull request to then be re-targetted to the Juju repo when ready to be
reviewed for real. Or does it?

Does anyone have any better ideas how to do this?