Add twitter badge

Author: kakawait

README.md

@@ -1,5 +1,7 @@
 # Tranquilpeak
 
+[![Twitter Follow](https://img.shields.io/twitter/follow/thibaudlepretre.svg?style=social&label=%40thibaudlepretre)](https://twitter.com/intent/follow?screen_name=thibaudlepretre)
+
 A gorgeous responsive theme for Hugo blog framework.
 
 ![Tranquilpeak](https://raw.githubusercontent.com/kakawait/hugo-tranquilpeak-theme/master/showcase.png)