Add usage (#1)

* Add usage

* Fix typo

* Add cloudnds perms in default node scopes

README.md

@@ -4,6 +4,38 @@
 
 This is a terraform module for creating a prow k8s cluster running in GKE.
 
+## Features
+
+- Runs in GKE
+- Runs on private nodes 
+- Managed Control Plane and Nodes by GKE
+- Automatic control plane upgrades
+- Automatic node updades
+- Cluster scales up and down as needed
+- Injected all needed secrets to install Prow
+- Setup GSuite integration with RBAC
+
+## Usage
+
+```
+module "prow-cluster" {
+  source = "git@github.com:ouzi-dev/prow-gke-terraform.git?ref=v0.1"
+
+  gcloud_region              = var.gcloud_region
+  gcloud_project             = var.gcloud_project
+  gke_kubernetes_version     = var.gke_kubernetes_version
+  dockerconfig_credstash_key = var.dockerconfig_credstash_key
+
+  base_domain = var.base_domain
+  github_org  = var.github_org
+
+  slack_bot_token_credstash_key = var.slack_bot_token_credstash_key
+  prow_artefact_bucket_location = var.prow_artefact_bucket_location
+
+  gke_authenticator_groups_security_group = var.gke_authenticator_groups_security_group
+}
+```
+
 ## Secrets
 
 We leverage [credstash](https://github.com/fugue/credstash) for managing secrets and therefore this module will require you to specify credstash keys

variables.tf

@@ -40,6 +40,7 @@ variable "gke_node_scopes" {
     "https://www.googleapis.com/auth/devstorage.read_write",
     "https://www.googleapis.com/auth/logging.write",
     "https://www.googleapis.com/auth/monitoring",
+    "https://www.googleapis.com/auth/ndev.clouddns.readwrite"    
   ]
 }