Added "Leaflet Tips and Tricks: Interactive Maps Made Easy"

free-programming-books.md

@@ -889,6 +889,7 @@
 * [Javascript Succinctly, Syncfusion](http://www.syncfusion.com/resources/techportal/ebooks/javascript) (PDF, Kindle) *(Just fill the fields with any values)*
 * [JS Robots](http://markdaggett.com/images/ExpertJavaScript-ch6.pdf)
 * [jQuery Fundamentals](http://jqfundamentals.com/book/) (starts with JavaScript basics)
+* [Leaflet Tips and Tricks: Interactive Maps Made Easy](https://leanpub.com/leaflet-tips-and-tricks) - Malcolm Maclean
 * [Learn to Code JavaScript by Playing a Game](http://codecombat.com)
 * [Learning JavaScript Design Patterns](http://www.addyosmani.com/resources/essentialjsdesignpatterns/book/) - Addy Osmani
 * [Managing Space and Time with JavaScript - Book 1: The Basics](http://www.noelrappin.com/)  - Noel Rappin