Readme needs an update

[XaverStiensmeier]

We can also add information regarding Docker to the readme @lukruh but I don't think it's a top priority ^^ in the end it doesn't hurt.

[lukruh]

I updated the install process in the readme and added testing and docker commands. I don't think they will be used a lot, so I don't spent much work on that. Anything else I could add on the fly with #63?

There are a few things we could improve to make the bot easier to use (maybe new issues?):

• provide a script that generates images in correct folders from downloaded zip or pdf files or
• zip and upload the resouces folder (as release not tracked by git)
• provide a ready to use docker image, that can be installed in a single command from github or docker.io