TODO: implement below
git-annex does use a lot of symlinks. Specicially, relative symlinks,
that are checked into git. To allow you to move those around without
annoyance, git-annex can run as a post-commit hook. This way, you can git mv
a symlink to an annexed file, and as soon as you commit, it will be fixed
up.
git annex init tries to set up a post-commit hook that is itself a symlink
back to git-annex. If you want to have your own shell script in the post-commit
hook, just make it call git annex with no parameters. git-annex will detect
when it's run from a git hook and do the necessary fixups.