document the system:masters privs

Documentation/k8s-pre-reqs.md

@@ -1,9 +1,16 @@
 
-**WARNING:** Kubernetes v1.6 or higher is targeted by Rook (while Rook is in alpha it will track the latest release to use the latest features). 
+## Minimum Version
+Kubernetes v1.6 or higher is targeted by Rook (while Rook is in alpha it will track the latest release to use the latest features). 
 
 Support is available for Kubernetes **v1.5.2**, although your mileage may vary. 
 You will need to use the yaml files from the [1.5 folder](/demo/kubernetes/1.5).
 
+## Privileges
+Creating the Rook operator requires privileges for setting up RBAC. To launch the operator you need to have created your user certificate with the `system:masters` privilege:
+```
+-subj "/CN=admin/O=system:masters"
+```
+
 ## Kubeadm
 
 You can easily spin up rook on top of a `kubeadm` cluster.

README.md

@@ -7,7 +7,7 @@
 - [What is Rook?](#what-is-rook)
 - [Status](#status)
 - [Quickstart Guides](#quickstart-guides)
-- [Troubleshooting Toolbox](#troubleshooting-toolbox)
+- [Advanced Configuration and Troubleshooting](#advanced-configuration-and-troubleshooting)
 - [Building](#building)
 - [Contributing](#contributing)
 - [Contact](#contact)