Document how one could use this on x86

[virtuald]

It seems that via use of qemu-arm-static you could potentially run this docker image on a normal PC. Need to explore that and document how it would be done.

• https://resin.io/blog/building-arm-containers-on-any-x86-machine-even-dockerhub/
• https://matchboxdorry.gitbooks.io/matchboxblog/content/blogs/build_and_run_arm_images.html