I think the latest version does not work with new repositories (existing repos work fine).

1. Clone locally
2. Create and git init new document repository
3. Update config.yaml
4. Start Jingo
5. Visit localhost:6067

Results in a runtime error:

/path/to/jingo/lib/gitmech.js:288
      callback(null, data.toString().split("\n"));
                         ^
TypeError: Cannot read property 'toString' of undefined
...

Looks like the hashes function blows up when there's no repo history.