added blue green strategy (#47)

* added blue green strategy

* Addressed review comments

* addressed pr comments

* updated names in test

* addressed final pr comments

__tests__/manifests/bg-smi.yml

@@ -0,0 +1,32 @@
+apiVersion : apps/v1beta1
+kind: Deployment
+metadata:
+  name: testapp 
+spec:
+  selector:
+    matchLabels:
+      app: testapp
+  replicas: 1
+  template:
+    metadata:
+      labels:
+        app: testapp 
+    spec:
+      containers:
+        - name: testapp 
+          image: testcr.azurecr.io/testapp
+          ports:
+          - containerPort: 80
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: testservice
+spec:
+  selector:
+    app: testapp
+  ports:
+    - protocol: TCP
+      port: 80
+      targetPort: 80
+---