Add a black style badge

Author: vtitor

Diff for: README.md

@@ -1,6 +1,9 @@
-PythonVerbalExpressions [![Build Status](https://travis-ci.org/VerbalExpressions/PythonVerbalExpressions.svg?branch=master)](https://travis-ci.org/VerbalExpressions/PythonVerbalExpressions)
+PythonVerbalExpressions
 =======================
 
+[![Build Status](https://travis-ci.org/VerbalExpressions/PythonVerbalExpressions.svg?branch=master)](https://travis-ci.org/VerbalExpressions/PythonVerbalExpressions)
+[![Code style: black](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/ambv/black)
+
 ## Installation
 ```bash
 pip install VerbalExpressions