Add notes about Wireguard

tasks/network.yml

@@ -1,3 +1,8 @@
+# Note that Wireguard does DNS resolution only once during connection.
+# When a client's IP changes, the server should be notified in some way,
+# using `wg set wg0 peer izHzmRwh2yzICps6pFI2Bg3TnmTD66/8uH4loJpkuD4= endpoint <NEW-IP>:<PORT>`
+# for example.
+
 - name: create wireguard directories
   become: true
   file: