logging client ip address behind reverse proxy

https://github.com/nextcloud/docker/issues/1103

docker.yml

@@ -90,6 +90,18 @@
           - python3-docker
         update_cache: yes
         install_recommends: no
+    
+    # https://github.com/nextcloud/docker/issues/1103
+    - name: writing daemon.json (ipv6 settings) 
+      copy:
+        dest: "/etc/docker/daemon.json"
+        content: |
+          {
+            "ipv6": true,
+            "fixed-cidr-v6": "fdab::/64",
+            "experimental": true, 
+            "ip6tables": true
+          }
 
     - name: /usr/local/sbin/autoupdate.d/docker.update
       blockinfile: