Add track NCCO code snippet

voice/track-ncco.py

@@ -0,0 +1,39 @@
+from flask import Flask, request, jsonify
+
+app = Flask(__name__)
+
+@app.route("/webhooks/answer")
+def answer_call():
+  ncco = [{
+      "action": "talk",
+      "text": "Thanks for calling the notification line"
+    },
+    {
+      "action": "notify",
+      "payload": {
+        "foo": "bar"
+      },
+      "eventUrl": [
+        "{url_root}webhooks/notification".format(url_root=request.url_root)
+      ]
+    },
+    {
+      "action": "talk",
+      "text": "You will never hear me as the notification URL will return an NCCO "
+    }]
+  return jsonify(ncco)
+
+@app.route("/webhooks/notification", methods=['POST'])
+def notification():
+  ncco = [{
+    "action": "talk",
+    "text": "Your notification has been received, loud and clear"
+  }]
+  return jsonify(ncco)
+
+@app.route("/webhooks/event", methods=['POST'])
+def event():
+  return "OK"
+
+if __name__ == '__main__':
+    app.run(host="localhost", port=3000)