Fix docker compose postgres volume path (#583)

Fix docker compose postgres volume

Partial revert of ac586b1.

The compose files previously used the mountpoint for postgres 18 containers (/var/lib/postgresql) on a postgres 17 container. Since the actual mountpoint, defined in the image as /var/lib/postgresql/data, is still free, a new unnamed volume was created for each container, resetting the database with every `docker compose down`.

Also locks the container version in the dev setup because the path will need to be changed back once the custom image is updated to postgres 18.

Author: MaximilianHausen

docker/dev/compose.yml

@@ -2,7 +2,7 @@ name: split-pro-dev
 
 services:
   postgres:
-    image: ossapps/postgres
+    image: ossapps/postgres:17.7-trixie
     container_name: ${POSTGRES_CONTAINER_NAME:-splitpro-db}
     restart: always
     environment:
@@ -11,7 +11,7 @@ services:
       - POSTGRES_DB=${POSTGRES_DB:-splitpro}
       - POSTGRES_PORT=${POSTGRES_PORT:-5432}
     volumes:
-      - database:/var/lib/postgresql
+      - database:/var/lib/postgresql/data
     command: >
       postgres
       -c shared_preload_libraries=pg_cron

docker/prod/compose.yml

@@ -24,7 +24,7 @@ services:
     #   - "5432:5432"
     env_file: .env
     volumes:
-      - database:/var/lib/postgresql
+      - database:/var/lib/postgresql/data
 
   splitpro:
     image: ossapps/splitpro:latest