Add postgres with healthcheck

mariadb/Dockerfile

@@ -1,3 +1,4 @@
+# checkov:skip=CKV_DOCKER_3 We're not adding a user, its coming down from on-high in mariadb.
 FROM mariadb:injected-version
 
 LABEL maintainer="Matthew Baggett <matthew@baggett.me>" \

postgres/Dockerfile

@@ -1,3 +1,4 @@
+# checkov:skip=CKV_DOCKER_3 We're not adding a user, its coming down from on-high in postgres.
 FROM postgres:injected-version
 
 LABEL maintainer="Matthew Baggett <matthew@baggett.me>" \

postgres/postgres_healthcheck.sh

@@ -1,2 +1,2 @@
 #!/bin/bash
-PG_PASSWORD=$POSTGRES_PASSWORD pg_isready -U "$POSTGRES_USER"
+PG_PASSWORD=${POSTGRES_PASSWORD} pg_isready -U "${POSTGRES_USER}"