Add Ember Observer badge to README

Author: soulim

README.md

@@ -1,6 +1,7 @@
 # Ember CLI datepicker add-on
 
 [![Build Status](https://travis-ci.org/soulim/ember-cli-bootstrap-datepicker.svg?branch=master&style=flat)](https://travis-ci.org/soulim/ember-cli-bootstrap-datepicker)
+[![Ember Observer Score](http://emberobserver.com/badges/ember-cli-bootstrap-datepicker.svg)](http://emberobserver.com/addons/ember-cli-bootstrap-datepicker)
 
 The add-on provides you a date input component based on amazing bootstrap-datepicker library. It supports popup and inline mode, and can be used in Ember CLI applications.
 
@@ -210,4 +211,4 @@ The add-on is based on [bootstrap-datepicker](https://github.com/eternicode/boot
 
 ## License
 
-[MIT License](https://github.com/soulim/ember-cli-bootstrap-datepicker/blob/master/LICENSE.md)
+[MIT License](https://github.com/soulim/ember-cli-bootstrap-datepicker/blob/master/LICENSE.md)