Add screenshot.

Author: khatchad

README.md

@@ -2,7 +2,8 @@
 
 [![Build Status](https://travis-ci.org/ponder-lab/Optimize-Java-8-Streams-Refactoring.svg?branch=master)](https://travis-ci.org/ponder-lab/Optimize-Java-8-Streams-Refactoring) [![Coverage Status](https://coveralls.io/repos/github/ponder-lab/Java-8-Stream-Refactoring/badge.svg?branch=master&t=mM9zgy)](https://coveralls.io/github/ponder-lab/Java-8-Stream-Refactoring?branch=master) [![GitHub license](https://img.shields.io/badge/license-Eclipse-blue.svg)](https://github.com/khatchadourian-lab/Java-8-Stream-Refactoring/raw/master/LICENSE.txt) [![DOI](https://zenodo.org/badge/78147265.svg)](https://zenodo.org/badge/latestdoi/78147265)
 
-<!-- TODO: ## Screenshot -->
+## Screenshot
+![Screenshot](http://i2.wp.com/khatchad.commons.gc.cuny.edu/files/2018/03/Screenshot-from-2018-04-28-17-34-53.png)
 
 ## Introduction