Add configmap deployment using support between formulas

Change-Id: Idf9ae2bd439ba315464e18188038d05b1e589f60
diff --git a/README.rst b/README.rst
index 7005d62..118efd8 100644
--- a/README.rst
+++ b/README.rst
@@ -430,6 +430,48 @@
                 mount: /certs
                 path: /etc/certs
 
+Configmap
+---------
+
+You are able to create configmaps using support layer between formulas.
+It works simple, eg. in nova formula there's file ``meta/config.yml`` which
+defines config files used by that service and roles.
+
+Kubernetes formula is able to generate these files using custom pillar and
+grains structure. This way you are able to run docker images built by any way
+while still re-using your configuration management.
+
+Example pillar:
+
+.. code-block:: bash
+
+    kubernetes:
+      control:
+        configmap:
+          nova-control:
+            grains:
+              # Alternate grains as OS running in container may differ from
+              # salt minion OS. Needed only if grains matters for config
+              # generation.
+              os_family: Debian
+            pillar:
+              # Generic pillar for nova controller
+              nova:
+                controller:
+                  enabled: true
+                  versionn: liberty
+                  ...
+
+To tell which services supports config generation, you need to ensure pillar
+structure like this to determine support:
+
+.. code-block:: yaml
+
+    nova:
+      _support:
+        config:
+          enabled: true
+
 Volumes
 -------