Config-vol parameter explanation docker

Can someone explain me how to use config file with docker image (I need it just to config push notifications).
There is something like config-vol parameter but I have no idea where to place config file using that parameter.

For reference you can look at my config file to see how I setup the parse server and dashboard:

Index file:

I don’t understand your answer. Let me explain you, I just want to run parse on docker with custom push notifications config. I don’t know how to do it. Where should I place the config file, that’s the main problem.