Support for docker secrets

It would be great if the docker image would support docker secrets, so that things like GitHub credentials can be safely stored without building them into the image or providing them through environment variables.

Start by locating the Docker image build and configuration entry points, then review how Docker secrets could provide GitHub credentials without embedding them in the image or passing them through environment variables. Done means the image supports securely stored Docker secrets and the required credential path is documented or verified.

Written by the indexing model from the issue text.