Update README with Black shield.

Author: rhthomas

README.md

@@ -1,12 +1,15 @@
-# Python-Interview-Problems-for-Practice [![star this repo](http://githubbadges.com/star.svg?user=devAmoghS&repo=Python-Interview-Problems-for-Practice)](http://github.com/ddavison/github-badges) [![fork this repo](http://githubbadges.com/fork.svg?user=devAmoghS&repo=Python-Interview-Problems-for-Practice)](http://github.com/ddavison/github-badges/fork)
+# Python-Interview-Problems-for-Practice
+
+[![star this repo](http://githubbadges.com/star.svg?user=devAmoghS&repo=Python-Interview-Problems-for-Practice)](http://github.com/ddavison/github-badges) [![fork this repo](http://githubbadges.com/fork.svg?user=devAmoghS&repo=Python-Interview-Problems-for-Practice)](http://github.com/ddavison/github-badges/fork) [![Code style: black](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/python/black)
+
 ![alt text](https://images.unsplash.com/photo-1494178270175-e96de2971df9?ixlib=rb-1.2.1&auto=format&fit=crop&w=972&q=80)
 40+ Common code and interview problems solved in Python (it's growing...)
 
 ### The core idea is not to utilize built-in functions or library and giving it a more logic-based approach, so that it can be language-friendly and not end up being another repository of "Python Tips and Tricks" .
 
 ## How good is the code ?
 * It is well tested
-* It passes style checks (PEP8 compliant) [TODO]
+* Consistent formatting (using [Black](https://github.com/python/black))
 * It can compile in its current state (and there are relatively no issues)
 
 ## How much support is available?