set -c config_file= in docker-compose

[wuputah]

fixes #130

This is the recommendation per the docs ( https://hub.docker.com/_/postgres/ ) that I was following, but I missed that they had -c 'config_file=...'.

[owenthereal]

Is this the default behaviour for the image? If so, I think it would be better to copy the config file and the change the running command in the image:

...

COPY ./files/postgres/postgresql.conf /etc/postgresql/postgresql.conf
CMD ["postgres",  "-c", "config_file=/etc/postgresql/postgresql.conf"]

Users could further override the config & the command as they see fit via the docker flags or in docker compose.

[wuputah]

it can [also] be done a different way, yes, but what's wrong with supporting this way? I'd like to just fix this for the moment. :)

[owenthereal]

but what's wrong with supporting this way?

It depends on how users run the image. If they run it without the docker-compose file (e.g. docker run ghcr.io/hydradatabase/hydra:latest), the default command and the config won't be in affect. That's why I was trying to clarify whether using the config and command is the default behavior of running the image :). If it is, moving both to the Dockerfile would be better.

I approved it in case you want to merge it as is.

[wuputah]

it's worthy of more thought, but let's not overthink it too much. user feedback welcome. :)