update the docs

README.md

@@ -1,6 +1,17 @@
 # BlacklightHeatmaps
 [![Build Status](https://travis-ci.org/sul-dlss/blacklight_heatmaps.svg?branch=master)](https://travis-ci.org/sul-dlss/blacklight_heatmaps) | [![Coverage Status](https://coveralls.io/repos/github/sul-dlss/blacklight_heatmaps/badge.svg?branch=master)](https://coveralls.io/github/sul-dlss/blacklight_heatmaps?branch=master)
 
+![blacklight_heatmap](https://cloud.githubusercontent.com/assets/1656824/16598401/d0538fce-42cb-11e6-86f8-81fd37ab2abe.gif)
+
+## Features
+ - Configurable heatmaps of result sets
+    - Works with center points and bounding box data
+ - Show page map view
+ - Changeout the basemap to any tile layer
+ - _Really_ fast with large data sets
+    - Utilizes Solr's [facet heatmap](https://issues.apache.org/jira/browse/SOLR-7005) feature to provide snappy results. Tested with an index > 10,000,000 records.
+ - Customizable result view template
+
 ## Installation
 
 Add this line to your application's Gemfile: