ALLOWED_HOSTS in a docker container

[Hritik14]

The documentation asks to populate ALLOWED_HOSTS in .env during the Run phase. This will have no effect inside the docker container. ALLOWED_HOSTS should be either

1. Placed before building the dockerfile so that .env gets copied inside the container and carries the ALLOWED_HOSTS value or
2. Be used inside docker.env.

2 appears to be a better approach in my opinion.