Update Traefik Forward Auth for v2 (#169)

_snippets/recipe-tfa-ingredients.md

@@ -0,0 +1,11 @@
+## Ingredients
+
+!!! summary "Ingredients"
+    Already deployed:
+
+    * [X] [Docker swarm cluster](/ha-docker-swarm/design/) with [persistent shared storage](/ha-docker-swarm/shared-storage-ceph.md)
+    * [X] [Traefik](/ha-docker-swarm/traefik) configured per design
+
+    New:
+
+    * [ ] DNS entry for your auth host (*"auth.yourdomain.com" is a good choice*), pointed to your [keepalived](/ha-docker-swarm/keepalived/) IP