add a copy of my mailing list post

doc/todo/gitolite_and_gitosis_support.mdwn

@@ -10,5 +10,25 @@ git-annex-shell subcommands to read-only users.
 I have posted an RFC for modifying gitolite to the
 [gitolite mailing list](http://groups.google.com/group/gitolite?lnk=srg).
 
+> I have not developed a patch yet, but all that git-annex needs is a way
+> to ssh to the server and run the git-annex-shell command there.
+> git-annex-shell is very similar to git-shell. So, one way to enable
+> it is simply to set GL_ADC_PATH to a directory containing git-annex-shell.
+> 
+> But, that's not optimal, since git-annex-shell will send off receive-pack
+> commands to git, which would bypass gitolite's permissions checking.
+> Also, it makes sense to limit readonly users to only download, not
+> upload/delete files from git-annex. Instead, I suggest adding something
+> like this to gitolite's config:
+ 
+	# If set, users with W access can write file contents into the git-annex,
+	# and users with R access can read file contents from the git-annex.
+	$GL_GIT_ANNEX = 0;
+
+> If this makes sense, I'm sure I can put a patch together for your
+> review. It would involve modifying gl-auth-command so it knows how
+> to run git-annex-shell, and how to parse out the "verb" from a
+> git-annex-shell command line, and modifying R_COMMANDS and W_COMMANDS.
+
 As I don't write python, someone else is needed to work on gitosis.
 --[[Joey]]