Add proper credit to XKCD to comply with their license

[codelitt]

In the interest of proper credit, should probably add a link and credit to the XKCD comic used here

Direct link to comic: https://xkcd.com/1168/

XKCD also provides a link for hotlinking/embedding which with attribution would be even better than just linking: http://imgs.xkcd.com/comics/tar.png

XKCD's license requests/requires this: https://xkcd.com/license.html

[santinic]

omg, I appreciate your concern, but life is so short man

[anuragaryan]

attribute fast or die tryin'.