Synchronize tracking repositories. Safe and simple one-script git synchronization.

This script intends to sync near-automatically via git in "tracking" repositories where a nice history is not as crucial as having one.

Suppose you have a set of text files you care about, multiple machines to work on, and a central git repository (a.k.a. bare repository) at your disposal. You do not care about atomic commits, but coarse versioning and backup is grave. For example, server configuration or org-mode files.