Added a simple arango + nginx template

I will tweet about this @rseymour . I was hoping to do something more complex as I do have a django + elasticsearch + mysql fig laying around, but I wanted to see if I could get something going with arango.  As it turns out my attempts with react/node/etc were too many new technologies at once.  This one is simply two servers that you can run between using javascript in an html file.

I provided the html and js needs (two files) here: https://github.com/rseymour/arango_demo If that falls outside the bounds of the contest I can merge them into the nginx Dockerfile.