Added more info to config section of README.md

[Lontronix]

No description provided.

[mxmeinhold]

Suggested change

	docker run --name postgres --mount target=/var/lib/postgresql/data,type=volume,src=conditional-db -e POSTGRES_PASSWORD=mysecretpassword -d -p 5432:5432 postgres
	docker run --name postgres -e POSTGRES_PASSWORD=mysecretpassword -d -p 5432:5432 postgres

You don't need to mount anything, the container db will persist as long as the container sticks around.

[mxmeinhold]

Also, you should change config.env.py to use the connection string for this as the default.