Docker Immutable Workstation

So I have used Docker to make my own immutable workstation. It means that I get exactly the same stack running on my banged-about-on-commute laptop, my wife's nice big screen iMac and even on my client's Windows box, that I had to use for client's policy reasons. So wherever I was, I was using the same config of emacs - using it on a windows machine or a mac or a linux host, it was the same emacs, and the same nice set of tools like grep. And it was running XWindows in those places too.