This commit allows compose file to directly use environment variable
values in "environment:" section when variables were set in `.env` file.
This functionality was missing, as docker-compose supports both: short
and variable interpolation syntax forms:
environment:
- FOO
and
environment:
- FOO=${FOO}
Relevant docker-compose documentation:
https://docs.docker.com/compose/how-tos/environment-variables/set-environment-variables/
podman-compose is more compatible with docker-compose after this change.
Signed-off-by: Monika Kairaityte <monika@kibit.lt>
