Add contrib/README.

Signed-off-by: Junio C Hamano <junkio@cox.net>

contrib/README

@@ -0,0 +1,44 @@
+Contributed Software
+
+Although these pieces are available as part of the official git
+source tree, they are in somewhat different status.  The
+intention is to keep interesting tools around git here, maybe
+even experimental ones, to give users an easier access to them,
+and to give tools wider exposure, so that they can be improved
+faster.
+
+I am not expecting to touch these myself that much.  As far as
+my day-to-day operation is concerned, these subdirectories are
+owned by their respective primary authors.  I am willing to help
+if users of these components and the contrib/ subtree "owners"
+have technical/design issues to resolve, but the initiative to
+fix and/or enhance things _must_ be on the side of the subtree
+owners.  IOW, I won't be actively looking for bugs and rooms for
+enhancements in them as the git maintainer -- I may only do so
+just as one of the users when I want to scratch my own itch.  If
+you have patches to things in contrib/ area, the patch should be
+first sent to the primary author, and then the primary author
+should ack and forward it to me (git pull request is nicer).
+This is the same way as how I have been treating gitk, and to a
+lesser degree various foreign SCM interfaces, so you know the
+drill.
+
+I expect that things that start their life in the contrib/ area
+to graduate out of contrib/ once they mature, either by becoming
+projects on their own, or moving to the toplevel directory.  On
+the other hand, I expect I'll be proposing removal of disused
+and inactive ones from time to time.
+
+If you have new things to add to this area, please first propose
+it on the git mailing list, and after a list discussion proves
+there are some general interests (it does not have to be a
+list-wide consensus for a tool targeted to a relatively narrow
+audience -- for example I do not work with projects whose
+upstream is svn, so I have no use for git-svn myself, but it is
+of general interest for people who need to interoperate with SVN
+repositories in a way git-svn works better than git-svnimport),
+submit a patch to create a subdirectory of contrib/ and put your
+stuff there.
+
+-jc
+