Added free CodeIgniter course, and organizing list by sub-categories (#4890)

* Update free-courses-pt_BR.md

* Update free-courses-pt_BR.md

* Update free-courses-pt_BR.md

* Update free-courses-pt_BR.md

Co-authored-by: Seth <seth@elypia.org>

* Update free-courses-pt_BR.md

Co-authored-by: Seth <seth@elypia.org>

* Update free-courses-pt_BR.md

Co-authored-by: Seth <seth@elypia.org>

* line spacing

* remove non-free ourse

Co-authored-by: Seth <seth@elypia.org>
Co-authored-by: Eric Hellman <eric@hellman.net>

free-courses-pt_BR.md

@@ -26,6 +26,7 @@
 * [Markdown](#markdown)
 * [Node.js](#nodejs)
 * [PHP](#php)
+  * [CodeIgniter](#codeIgniter)
 * [Python](#python)
 * [React Native](#react-native)
 * [Ruby](#ruby)
@@ -208,7 +209,6 @@
 * [Boas práticas em PHP](https://www.udemy.com/boas-praticas-em-php/) - Diego Mariano (Udemy)
 * [Curso Básico de Bootstrap 4 , PHP e MySQL](https://www.udemy.com/curso-basico-de-bootstrap-4-php-e-mysql-gratis/) - Ricardo Milbrath Gonçalves (Udemy)
 * [Introdução à Criação de Sites Dinâmicos com PHP](https://www.udemy.com/criacao-de-paginas-de-internet-dinamicas-com-php-basico/) - Diego Mariano (Udemy)
-* [Introdução ao Laravel (5.3)](https://www.udemy.com/introducao-ao-laravel-53/) - Guilherme Ferreira (Udemy)
 * [Introdução ao PHP orientado a objetos](https://www.udemy.com/php-orientado-a-objetos/) - Diego Mariano (Udemy)
 * [Lógica de Programação com PHP](https://www.youtube.com/playlist?list=PLhTDLccA9vgHHwGZArcUqIZ5AUGwrbZ_A) - Curso Zend Framework (YouTube)
 * [Login com validação e flash messages (PHP)](https://www.udemy.com/login-com-validacao-e-flash-messages-php/) - Alexandre Cardoso (Udemy)
@@ -217,6 +217,11 @@
 * [PHP para quem entende PHP](https://www.udemy.com/php-para-quem-entende-php/) - Alexandre Cardoso (Udemy)
 
 
+#### CodeIgniter
+
+* [Curso de CodeIgniter para iniciantes](https://www.youtube.com/playlist?list=PLInBAd9OZCzz2vtRFDwum0OyUmJg8UqDV) - RBtech
+
+
 ### Python
 
 * [Algoritmos em Python](https://algoritmosempython.com.br) - Douglas do Couto