How to invoke custome settings in docker backstop

I pullled the docker image for backstopjs (docker pull backstopjs/backstopjs)

The default test present in the package is running. But i want to change the settings as per my need. i have some custom scripts to be part of the execution.

1. How can i change the backstop.settings.js present inside docker container src/backstopjs?
2. How to refer to my own backstop.settings.js using docker?

e.g
backstop reference --config=my_backstop-settings.js --pathfile=readcsv2.js