Add more informations on README

Author: madeindjs

README.md

@@ -2,10 +2,26 @@
   <img src="img/logo.svg" alt="Api on Rails 5" />
 </h1>
 
-<noscript><a href="https://liberapay.com/alexandre_rousseau/donate"><img alt="Donate using Liberapay" src="https://liberapay.com/assets/widgets/donate.svg"></a></noscript>
+Learn **best practices** to build an **API** using **Ruby on Rails** 5. The intention with this book it’s not only to teach you how to build an API with Rails. The purpose is also to teach you how to build **scalable** and **maintainable** API with Rails which means **improve** your current Rails knowledge. In this book you will learn to:
+
+- Build JSON responses
+- Use Git for version controlling
+- Testing your endpoints
+- Optimize and cache the API
+
+This book is based on ["APIs on Rails: Building REST APIs with Rails"](http://apionrails.icalialabs.com/book/). It was initially published in 2014 by [Abraham Kuri](https://twitter.com/kurenn). Since the original work was not maintained, I wanted to update this excellent work. All the source code of this book is available in [Asciidoctor](https://asciidoctor.org/) format on this repository. So don’t hesitate to [fork the project](https://github.com/madeindjs/api_on_rails/fork) if you want to improve it or fix a mistake that I didn’t notice.
 
 Update & translation of the [API on Rails (EN)](http://apionrails.icalialabs.com/book) book. This book is written using [Asciidoctor](https://asciidoctor.org).
 
+## Support the project
+
+As you may know this project take me some times. So if you want to support me you can buy a version on Leanpub:
+
+- [English version](https://leanpub.com/apionrails5/)
+- [French version](https://leanpub.com/apionrails5/)
+
+Or you can support me with Liberapay: <noscript><a href="https://liberapay.com/alexandre_rousseau/donate"><img alt="Donate using Liberapay" src="https://liberapay.com/assets/widgets/donate.svg"></a></noscript>
+
 ## Build book
 
 ~~~bash