How are you running the Docker containers in production? e.g., Docker Compose on a single server, Kubernetes, something else, etc

For prod, if you are trying to keep runtime simple, I would bake the content into the Docker containers and keep the containers immutable as others have suggested. This works especially well if you're deploying on a FaaS platform like Zeit Now. Baking the content into the image makes scaling effortless if you need it.

For local dev, I would just use a docker volume or bind mount.