Use single internal network

compose.yml

@@ -6,7 +6,7 @@ services:
     image: nginx:1.19.2
     networks:
       - proxy
-      - app
+      - internal
     volumes:
       - /etc/timezone:/etc/timezone:ro
       - /etc/localtime:/etc/localtime:ro
@@ -56,10 +56,7 @@ services:
         mode: 0555
     entrypoint: /docker-entrypoint.sh
     networks:
-      app:
-      postfix_smtp:
-      redis:
-      db:
+      - internal
     depends_on:
       - db
       - redis
@@ -81,27 +78,19 @@ services:
     volumes:
       - postgres-data:/var/lib/postgresql/data
     networks:
-      db:
+      - internal
 
   cache:
     image: redis:4-alpine
     volumes:
       - redis-data:/data
     networks:
-      redis:
+      - internal
 
 networks:
+  internal:
   proxy:
     external: true
-  app:
-    driver: overlay
-    attachable: true
-  redis:
-    driver: overlay
-    attachable: true
-  db:
-    driver: overlay
-    attachable: true
 
 volumes:
   app-data: