nogit: Using git to track files without the user using git

Summary
=======
Let's see, nogit is a very simple tool that uses git under the hood to
allow for collaboration on files, but without requiring the the
collaborators to invoke git commands. Any time a user might invoke
"git commit", or "git push", or "git pull", etc. the user instead just
invokes "nogit sync". And the user will not be prompted to fill out a
commit message or to resolve conflicts, etc.

Installation
============
The nogit implementation is a simple bash script named "nogit". To
install it, simply copy it to a directory on your PATH. Or, if you'd
like to be able to follow along with nogit changes from a git
repository, you might create a symlink from a directory on your PATH
to the nogit script in the git repostiory.

Usage
=====
Presumably, you've been pointed to a repository which is intended to
be used with nogit. These repositories are often paired with a
"parent" repository that is being tracked with git. If so, the
procedure for cloning should look something like this:

	git clone /url/of/parent
        cd parent
        nogit clone /url/of/nogit/child

And after that, you can run "nogit sync" whenever convenient, (when
you've made changes or you think there might be upstream changes to
the files being tracked in the nogit repository). Note that "nogit
sync" should not ever ask for user input, so it's appropriate to call
"nogit sync" from an autoamted system, (such as a text editor's hook
when saving a file).

If you're interested in setting up a parent and child repository for
use with nogit, here's what you'll want to do:

    In the parent repository
    ------------------------
    Add the following to .gitignore:
       .nogit
       .gitattributes
       Any files to be tracked in the child nogit repository

    For the child repository
    ------------------------
    Create a new git repository
    Add the files to be tracked via nogit
    Add a .gitattributes file with contents such as:

	* merge=union

    The * is a pattern to match the files you're tracking. You don't
    necessarily need to use '*' you can explicitly name the files of
    interest. But the important thing is that all files tracked by
    nogit use the "union" merge driver (so that merges don't result in
    conflicts requiring user intervention).

Motivation
==========

I originally came up with nogit when I started maintaining a simple
TODO file for a project which had a code implementation split across
multiple code repositories. I was intentionally keeping my TODO file
outside of revision control to be lightweight in a couple of ways:

  1. Many TODO items required implementing a feature in multiple
     repositories (both client and server, say), so having a separate
     TODO file meant I didn't need to decide which repository to add
     the TODO file to. And I also didn't need to add the same entriy
     to TODO files in each of multiple repositories.

  2. TODO items are self-descriptive. Any commit message I might have
     written when adding a TODO item would be adequate as "Add <item>"
     and similarly for "Remove <item>" so there's inherently no
     advantage to commit messages for these changes.

Of course, a significant disadvantage of my approach was that my TODO
file was totally private. I was missing out on the collaborative
features that git provides.

So, nogit was conceived of as a way to keep my lightweight process of
maintaining the TODO file, (simply editing the file and doing nothing
more), while also allowing for distributed editing of the file.