Update free-books.md

Author: arpit1997

extras/free-books.md

@@ -112,6 +112,7 @@ Name | Author(s)
 Name | Author(s)
 :-- | :--:
 [Deep Learning](http://www.deeplearningbook.org/) | Ian Goodfellow, Yoshua Bengio and Aaron Courville
+[Bayesian Reasoning and Machine Learning](http://web4.cs.ucl.ac.uk/staff/D.Barber/pmwiki/pmwiki.php?n=Brml.HomePage) | David Barber
 
 ### Natural Language Processing