Removed trailing slash that broke Travis build.

free-programming-books.md

@@ -367,7 +367,7 @@
 * [A First Encounter with Machine Learning](https://www.ics.uci.edu/~welling/teaching/ICS273Afall11/IntroMLBook.pdf) (PDF)
 * [An Introduction to Statistical Learning](http://www-bcf.usc.edu/~gareth/ISL/) - Gareth James, Daniela Witten, Trevor Hastie and Robert Tibshirani
 * [Bayesian Reasoning and Machine Learning](http://web4.cs.ucl.ac.uk/staff/D.Barber/pmwiki/pmwiki.php?n=Brml.HomePage)
-* [Deep Learning](http://www.deeplearningbook.org/) - Ian Goodfellow, Yoshua Bengio and Aaron Courville
+* [Deep Learning](http://www.deeplearningbook.org) - Ian Goodfellow, Yoshua Bengio and Aaron Courville
 * [Gaussian Processes for Machine Learning](http://www.gaussianprocess.org/gpml/)
 * [Information Theory, Inference, and Learning Algorithms](http://www.inference.phy.cam.ac.uk/itila/)
 * [Introduction to Machine Learning](http://arxiv.org/abs/0904.3664v1) - Amnon Shashua