set default image as public existing image + update README

Author: huxcrux

README.md

@@ -2,6 +2,27 @@
 
 A tiny controller for persisting labels and taints on a list of nodes.
 
-## NodeGroup
 
-The NodeGroup schema can be found in `api/v1alpha/nogroup_types.go`.
+## Deploy controller and CRD
+
+```bash
+kustomize build config/default | kubectl apply -f -
+```
+
+## Sample nodegroup manifest
+
+```yml
+apiVersion: k8s.elx.cloud/v1alpha1
+kind: NodeGroup
+metadata:
+  name: nodegroup-sample
+spec:
+  members:
+    - node1 # Kubernetes node name
+  labels:
+    name: value
+  taints:
+    - effect: "NoSchedule"
+      key: key
+      value: value
+```

config/manager/kustomization.yaml

@@ -1,10 +1,18 @@
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+
 resources:
-- manager.yaml
+  - manager.yaml
 
 generatorOptions:
   disableNameSuffixHash: true
 
 configMapGenerator:
-- name: manager-config
-  files:
-  - controller_manager_config.yaml
+  - files:
+      - controller_manager_config.yaml
+    name: manager-config
+
+images:
+  - name: controller
+    newName: quay.io/elastx/elx-nodegroup-controller
+    newTag: v0.1