fix(Postgres): Add container name or postgres by default on postgres host

grafana/docker-compose.postgres.yml

@@ -5,7 +5,7 @@ services:
     environment:
       # https://grafana.com/docs/grafana/latest/administration/configuration/#database
       GF_DATABASE_TYPE: postgres
-      GF_DATABASE_HOST: postgres # Name is same as ../postgres/docker-compose.yml:8
+      GF_DATABASE_HOST: ${POSTGRES_CONTAINER_NAME:-postgres} # Default name is same as ../postgres/docker-compose.yml:8
       GF_DATABASE_NAME: ${POSTGRES_DB:?err}
       GF_DATABASE_USER: ${POSTGRES_USER:?err}
       GF_DATABASE_PASSWORD: ${POSTGRES_PASSWORD:?err}