Create API to track subscriptions and receive push notifications in Angular

Use the server from pluralsight/web-push-server as a starting point.

Author: agmo

angular/README.md

@@ -19,3 +19,14 @@ This project was generated with [Angular CLI](https://github.com/angular/angular
  ```
 
 1. Navigate to `http://localhost:8080/`.
+
+1. Start the server that keeps track of subscribers:
+
+ ```
+ node angular/web-push-server/app.js
+ ```
+
+1. Click Enable Push Notifications (if notifications are already enabled, 
+ disable them and then enable them again). 
+ 
+ Notifications will be sent every 30 seconds.