Coding Challenges

[weaverryan]

I've added 1 coding challenge, but I've written a few other ones. I would love to have coding challenges for this for next week so that people can actually code to learn this stuff :).

https://github.com/knpuniversity/php-namespaces-in-120-seconds/blob/master/knpu/challenge_notes.md

Ping @bocharsky-bw