documentation for committing with git

At the developer meeting, I promised to do the work of documenting how
committers should use git.  So here's a first version.

http://wiki.postgresql.org/wiki/Committing_with_Git

Note that while anyone is welcome to comment, I mostly care about
whether the document is adequate for our existing committers, rather
than whether someone who is not a committer thinks we should manage
the project differently... that might be an interesting discussion,
but we're theoretically making this switch in about a month, and
getting agreement on changing our current workflow will take about a
decade, so there is not time now to do the latter before we do the
former.  So I would ask everyone to consider postponing those
discussions until after we've made the switch and ironed out the
kinks.  On the other hand, if you have technical corrections, or if
you have suggestions on how to do the same things better (rather than
suggestions on what to do differently), that would be greatly
appreciated.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise Postgres Company