Add Dockerfile

[dxspotxfinsxnity]

It would be useful to have an instruction on how to self-host Verdaccio website using Docker for offline use.

[juanpicado]

could you detail more your scenario?

[dxspotxfinsxnity]

I was having trouble building a Docker image for the website, but as it turns out it was pretty straightforward in the end. You may close the issue as it's no longer relevant to me.