add required networks

README.md

@@ -1,6 +1,15 @@
 # Basic Caddy docker-compose config
-* can be run on single node setup or in swarm  
-* recommend to set `replicas` on 2 or more if deploy in swarm
+- can be run on single node setup or in swarm  
+- recommend to set `replicas` on 2 or more if deploy in swarm
+- default setup requires 2 external networks
+    - Services with exposed Ports should be in frontend network
+    - Services only accessable for caddy should be in backend network
+    - on single host:
+        - docker network create frontend
+        - docker network create backend
+    - on swarm:
+        - docker network create --scope=swarm --attachable -d overlay frontend
+        - docker network create --scope=swarm --attachable -d overlay backend
 
 ## howto
 ### single node