adding support to FILE suffix

[guydou]

The FILE suffix is supporeted in docker-entry of postgres image, but was removed when the ./docker-entry.sh was overriden

so I added that support,

also the setup_replication.sh f needed the password that comes from file, so I added that there as well

[DanielDent]

Thanks for the pull request. Looking pretty good - one quick question below.

[DanielDent]

What if only PGPASSWORD is set & POSTGRES_PASSWORD isn't?

[guydou]

I don't understand the question, POSTGRES_PASSWORD has to be set, otherwise the scripts will not work regradless of my change, am I missing something?

the reason I added PGPASSWORD=${POSTGRES_PASSWORD} is to make the ping to master to work, since this script need the password in order to work

[DanielDent]

I apologize I did not previously have time to properly review and merge your work.

I've created a new patch based build process on the dev branch, and builds from this process temporarily live at https://hub.docker.com/r/danieldent/docker-postgres-replication-dev/ until I and other community members have had a chance to test these updates (the new build process also builds the -alpine variants as well as Postgres 10). I have not had time to even run these new builds, so please run this builds in test prior to dropping them into a production environment.