add gem version and build status badges

Author: codebender

README.md

@@ -1,6 +1,10 @@
 # OmniAuth OAuth2 strategy for Fitbit
 This gem is an OAuth2 OmniAuth Strategy for the [Fitbit API](https://wiki.fitbit.com/display/API/OAuth+2.0).
 
+## Gem Status
+[![Gem Version](https://badge.fury.io/rb/omniauth-fitbit-oauth2.svg)](http://badge.fury.io/rb/omniauth-fitbit-oauth2)
+[![Build Status](https://semaphoreci.com/api/v1/projects/2fae3e5c-5bb1-4cf6-8d58-de1656ff3751/425290/shields_badge.svg)](https://semaphoreci.com/codebender/omniauth-fitbit-oauth2)
+
 ## Installing
 
 Add to your `Gemfile`: