add notice of routesrv proxy enabled

Signed-off-by: Troy Kohler <troy.kohler@zalando.de>

docs/tutorials/ratelimit.md

@@ -115,7 +115,11 @@ Redis based Cluster Ratelimits](../kubernetes/ingress-controller.md#redis-based)
 
 #### Redis Swarm Configuration
 
-When working with redis swarm, use kubernetes service selector. Configure it with `-kubernetes-redis-service-namespace` and `-kubernetes-redis-service-name` flags. Skipper auto-discovers new redis instances each 10 seconds using background routine. 
+When working with redis swarm, use kubernetes service selector. Configure it with `-kubernetes-redis-service-namespace` and `-kubernetes-redis-service-name` flags.
+
+Auto-discovery routine for new redis endpoints will be triggered every 10 seconds.
+
+If you have [routesrv proxy](https://opensource.zalando.com/skipper/kubernetes/ingress-controller/#routesrv) enabled, you need to configure skipper with the flag `-swarm-redis-remote` where remote value will be the service address for `routesrv` service. `Routesrv` will be responsible for collecting redis endpoints and skipper will poll them from the proxy.
 
 #### Implementation