Mounting that file via docker won't do anything as it does not exist in the built image, it's only used during the build. Therefore you have to clone, edit the file, build, and then deploy.
I could be wrong but I've read the docs thoroughly (https://casibase.org/docs/basic/try-with-docker is the relevant section for Docker) and tried configuring via environment variables and mounting the config file, and it still redirects to door.casdoor.com.

