Add to docs: with the default config in the README, where is the configuration saved?

[DeflateAwning]

Please add this info to the docs (README): with the default config (default docker run command) in the README, where is the configuration saved?

[dusdoom]

Some of my friends went through this problem earlier when trying to store their stuff in another drive.
I think we should probably change the volume to a bind mount instead of a module or at least give a reference for the user to understand the difference between both of them.