update readme

README.md

@@ -3,17 +3,17 @@
 A very fast JavaScript library for geospatial point clustering for browsers and Node.
 
 ```js
-const index = new Supercluster({
-    radius: 40,
-    maxZoom: 16
-});
+const index = new Supercluster({radius: 40, maxZoom: 16});
 index.load(points);
-index.getClusters([-180, -85, 180, 85], 2);
+
+const clusters = index.getClusters([-180, -85, 180, 85], 2);
 ```
 
 Clustering 6 million points in Leaflet:
 
-![clusters2](https://cloud.githubusercontent.com/assets/25395/11857351/43407b46-a40c-11e5-8662-e99ab1cd2cb7.gif)
+![clustering demo on an interactive Leaflet map](https://cloud.githubusercontent.com/assets/25395/11857351/43407b46-a40c-11e5-8662-e99ab1cd2cb7.gif)
+
+Supercluster was built to power clustering in [Mapbox GL JS](https://www.mapbox.com/mapbox-gljs). Read about how it works [on the Mapbox blog](https://blog.mapbox.com/clustering-millions-of-points-on-a-map-with-supercluster-272046ec5c97).
 
 ## Install