Add Fetch example (firebase#105)

FluorescentHallucinogen · nicolasgarnier · commit c159296556d6 · 2017-03-05T12:50:57.000-08:00
diff --git a/messaging/README.md b/messaging/README.md
@@ -46,6 +46,34 @@ Content-Type: application/json
 }
 ```
 
+### Fetch
+```js
+var key = 'YOUR-SERVER-KEY';
+var to = 'YOUR-IID-TOKEN';
+var notification = {
+  'title': 'Portugal vs. Denmark',
+  'body': '5 to 1',
+  'icon': 'firebase-logo.png',
+  'click_action': 'http://localhost:8081'
+};
+
+fetch('https://fcm.googleapis.com/fcm/send', {
+  'method': 'POST',
+  'headers': {
+    'Authorization': 'key=' + key,
+    'Content-Type': 'application/json'
+  },
+  'body': JSON.stringify({
+    'notification': notification,
+    'to': to
+  })
+}).then(function(response) {
+  console.log(response);
+}).catch(function(error) {
+  console.error(error);
+})
+```
+
 ### cURL
 ```
 curl -X POST -H "Authorization: key=YOUR-SERVER-KEY" -H "Content-Type: application/json" -d '{
