Add RPi assets post Dockercon

[alexellis]

Hi @ManoMarks ,

I had a request from @jrburcio to link out to the RPi workshop I put together for Dockercon. I've also had lots of interest around Docker and the RPi recently so wanted to put together some core links to help people get started.

(All of the linked posts are in a lab/tutorial format.)

This was the "5 things" post over the weekend:

https://twitter.com/alexellisuk/status/863380405680001024

Alex

[ManoMarks]

Hi Alex,

Since these are all hosted external to the Labs repo, let's instead put them on the /README.md under Community tutorials. In the future, if we come up with a larger set of community tutorials we want to link to, we can create a separate categorized page.

[alexellis]

Hi @ManoMarks No problems, I've made the amendments and re-pushed.