Fixed references to old Bulletin Board demo

The current documentation references the newer todo list built in the [Getting Started demo](https://docs.docker.com/get-started/02_our_app/) built in previous steps, but the docs listed the code for the older [BulletinBoard:1.0 image](http://www.myclass5.cn/get-started/part2/). So, this patch applies the following to run Getting Started:

- changed the name of the image to `getting-started`, and rebuild the image using `docker build -t getting-started .`
- changed the port numbers under the `ports` key in the Kubernetes YAML to *3000*

get-started/kube-deploy.md

@@ -44,7 +44,7 @@ All containers in Kubernetes are scheduled as _pods_, which are groups of co-loc
         spec:
           containers:
           - name: bb-site
-            image: bulletinboard:1.0
+            image: getting-started
     ---
     apiVersion: v1
     kind: Service
@@ -56,8 +56,8 @@ All containers in Kubernetes are scheduled as _pods_, which are groups of co-loc
       selector:
         bb: web
       ports:
-      - port: 8080
-        targetPort: 8080
+      - port: 3000
+        targetPort: 3000
         nodePort: 30001
     ```