Merge "Add Redis component to README.rst"

README.rst

@@ -107,6 +107,7 @@ Kolla-Ansible deploys containers for the following infrastructure components:
 - `Open vSwitch <http://openvswitch.org/>`__ and Linuxbridge backends for Neutron.
 - `RabbitMQ <https://www.rabbitmq.com/>`__ as a messaging backend for
   communication between services.
+- `Redis <https://redis.io/>`__ an in-memory data structure store.
 
 Directories
 ===========