It\'s quite easy to mount a host directory in the docker container.
But I need the other way around.
I use a docker container as a development environment fo
Copying the WordPress files to the mounted folder was the solution.
I move the files in the container from the original folder to the mounted folder and use symbolic links to link them back to the original folder.
The important part is, the container can follow symbolic links in the container and but the host can't. So just using symbolic links from the original folder to the mounted folder doesn't work, because the host cannot follow symbolic links in the container!