Added The Agile Idea

Hi,

Stjepan from Manning here. I thought this title might be a good match for your list. Thank you for considering it.

Best,

Author: stjepanjurekovic

README.md

@@ -67,6 +67,7 @@
 - [Understanding the Agile methodology](https://linchpinseo.com/the-agile-method/)
 - [Agile ceremonies](https://www.atlassian.com/agile/scrum/ceremonies)
 - [Agile user stories](https://zepel.io/agile/user-stories/)
+- [The Agile Idea](https://www.manning.com/books/the-agile-idea)
 
 ## Android