add warning to Zookeeper example
Replicated ZooKeeper Template
=============================
+WARNING: This is a toy example and is NOT SUITABLE FOR PRODUCTION USE. It
+instantiates Pods directly rather than through a StatefulSet object, therefore
+the Pods are not resilient in face of an application crash or eviction.
+
ZooKeeper is a distributed, open-source coordination service for distributed
applications. It exposes a simple set of primitives that distributed
applications can build upon to implement higher level services for
