updates

README.md

@@ -79,6 +79,7 @@ If you want to contribute to this list, send me a pull request or contact me [@j
 * [Machine Learning Ruby](https://github.com/mizoR/machine-learning-ruby)
 * [jRuby Mahout](https://github.com/vasinov/jruby_mahout) - JRuby Mahout is a gem that unleashes the power of Apache Mahout in the world of JRuby.
 * [CardMagic-Classifier](https://github.com/cardmagic/classifier) - A general classifier module to allow Bayesian and other types of classifications.
+* [Neural Networks and Deep Learning](https://github.com/mnielsen/neural-networks-and-deep-learning) - Code samples for my book "Neural Networks and Deep Learning"
 
 #### Data Analysis / Data Visualization