Add binder link

Author: mrkn

README.md

@@ -2,6 +2,7 @@
 
 [![Gem Version](https://badge.fury.io/rb/iruby.svg)](https://badge.fury.io/rb/iruby)
 [![Build Status](https://travis-ci.org/SciRuby/iruby.svg?branch=master)](https://travis-ci.org/SciRuby/iruby)
+[![Binder](https://mybinder.org/badge_logo.svg)](https://mybinder.org/v2/gh/RubyData/binder/master?filepath=ruby-data.ipynb)
 
 IRuby is a Ruby kernel for [Jupyter project](http://try.jupyter.org/).