add printables to contact page

input/contact.md

@@ -9,4 +9,5 @@ You can always use this [PGP Key](files/xythobuz.asc)!
 * Mail: <thomas@xythobuz.de>
 * Twitter: [@xythobuz](https://twitter.com/xythobuz)
 * Youtube: [xythobuz](http://www.youtube.com/user/xythobuz)
+* Printables [xythobuz](https://www.printables.com/social/216011-xythobuz)
 * Thingiverse: [xythobuz](https://www.thingiverse.com/xythobuz/designs)