it's more like a gist than a git ^^ Other things:

- it's something posted on stackoverflow, I assume it's public domain;
- at first I wanted to use it all, but I only used the init function and inspired the `changes` method from the other methods, before deleting them.

I'm not sure about the use of a submodule; if it were more complete, why not, but I could have done it myself, I just wandered on the web to find something like this quickly.