books: add Caleb's book from O'Reilly

Books.md

diff --git a/Books.md b/Books.md
index 7a0ec8f..2dd0545 100644
--- a/Books.md
+++ b/Books.md
@@ -106,6 +106,12 @@
     * ISBN: 978-0134190440
     * Reference: http://www.gopl.io/
 
+  * **Introduction to Programming in Go**
+    * Author: Caleb Doxsey
+    * Publication Date: January 2016
+    * ISBN: 978-1491941959
+    * Reference: http://shop.oreilly.com/product/0636920046516.do
+
 ## Available without Publication Date
 
   * **Learning Go** (e-book)