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
+---

__tests__/manifests/bg.yml

@@ -0,0 +1,85 @@
+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
+---
+apiVersion: networking.k8s.io/v1beta1
+kind: Ingress
+metadata:
+  name: testingress
+  annotations:
+    nginx.ingress.kubernetes.io/rewrite-target: /
+spec:
+  rules:
+  - http:
+      paths:
+      - path: /testpath
+        pathType: Prefix
+        backend:
+          serviceName: testservice
+          servicePort: 80
+---
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: testconfigmap
+data:
+  # property-like keys; each key maps to a simple value
+  whats_this: "testing"
+  why_this: "testing"
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: testservice-2
+spec:
+  selector:
+    app: testapp-2
+  ports:
+    - protocol: TCP
+      port: 80
+      targetPort: 80
+---
+apiVersion: networking.k8s.io/v1beta1
+kind: Ingress
+metadata:
+  name: testingress-1
+  annotations:
+    nginx.ingress.kubernetes.io/rewrite-target: /
+spec:
+  rules:
+  - http:
+      paths:
+      - path: /testpath
+        pathType: Prefix
+        backend:
+          serviceName: testnotservice
+          servicePort: 80
+---