add slirp4netns network_mode option

templates/docker-compose.yml.j2

@@ -5,6 +5,7 @@ services:
     # Note: Check the recommend version here: https://docs.nextcloud.com/server/latest/admin_manual/installation/system_requirements.html#server
     image: postgres:alpine
     hostname: db
+    network_mode: slirp4netns
     restart: always
     volumes:
       - db:/var/lib/postgresql/data:Z
@@ -20,6 +21,7 @@ services:
   app:
     image: nextcloud:fpm-alpine
     hostname: app
+    network_mode: slirp4netns
     restart: always
     volumes:
       - nextcloud:/var/www/html:z
@@ -39,6 +41,7 @@ services:
   web:
     image: nginx:alpine-slim
     hostname: web
+    network_mode: slirp4netns
     restart: always
     volumes:
       # https://docs.nextcloud.com/server/latest/admin_manual/installation/nginx.html
@@ -58,7 +61,7 @@ services:
   cron:
     image: nextcloud:fpm-alpine
     hostname: cron
-    restart: always
+    network_mode: slirp4netns
     restart: always
     volumes:
       - nextcloud:/var/www/html:z
@@ -74,6 +77,7 @@ services:
   proxy:
     build: ./proxy
     hostname: proxy
+    network_mode: slirp4netns
     restart: always
     ports:
       - 8080:80