Adding the API with Silex on GAE ebook, in pt_BR, PHP Section. (#2242)

* Adding the API with Silex on GAE ebook, in pt_BR, PHP Section.

* Adding the API with Silex on GAE ebook, in pt_BR, PHP Section.

* Alphabetize the PHP ebooks in pt_BR.

free-programming-books-pt_BR.md

@@ -132,6 +132,7 @@
 ### PHP
 
 * [A semana PHP](http://asemanaphp.com.br)
+* [Api REST Com Silex no GAE](http://bit.ly/ebook-silex) - Nanderson Castro [(PDF, EPUB, MOBI)]
 * [CakePHP](http://book.cakephp.org/2.0/pt/index.html)
 * [Curso Linguagem PHP 2000](http://www.etelg.com.br/paginaete/downloads/informatica/php.pdf) (PDF)
 * [Laravel - O Framework PHP para os Artesãos da Web](http://laravel.artesaos.org)