add coverage for Fourchette::GitHub

Now I understand why my last push to #29 didn't change coverage that much....

![](http://i0.kym-cdn.com/entries/icons/original/000/000/554/facepalm.jpg)
Place the . on the previous line, together with the method call receiver.<br>Prefer double-quoted strings unless you need single quotes to avoid extra backslashes for escaping.