Update README.md

Author: tigoCaval

README.md

@@ -3,6 +3,8 @@ Collaborative filtering recommendation system
 - Ranking algorithm using likes / dislikes or star-based rating
 - This package can be used in any PHP application or with any framework.
 - Download package: ```composer require tigo/recommendation```
+---
+*If you found this project useful, consider making a donation to support the developer [Donate](https://www.paypal.com/donate?hosted_button_id=S7FBV5N6ZTRXQ)*
 
  ### Getting started
  Starting with composer