VTOP in Docker Container

[snpranav]

I created a Dockerfile which creates an image for vtop and can be accessed at snpranav/vtop. The reason behind doing this was to make vtop more cross-platform. This also lets people use vtop without having to install Node.js on their host machine (All you need is docker).

I have also updated the README with instructions on how to run vtop as a docker container.