move from bind mounts to named volumes

keycloak/docker-compose.yml

@@ -5,7 +5,7 @@ services:
   postgres:
       image: postgres:15.5-alpine3.19
       volumes:
-        - ./postgres_data:/var/lib/postgresql/data
+        - postgres_volume:/var/lib/postgresql/data
       environment:
         POSTGRES_DB: keycloak
         POSTGRES_USER: keycloak
@@ -46,4 +46,8 @@ services:
 
 networks:
   bizmatch:
+    external: true
+
+volumes:
+  postgres_volume:
     external: true