adding portuguese support

README.md

@@ -92,6 +92,8 @@ Thanks [Jae Hyun Yoo](https://www.facebook.com/fkkcloud) for the Korean [transla
 
 Thanks [Nahuel Coppero (Necsoft)](http://hinecsoft.com/) for the Spanish [translation (español)](?lan=es)
 
+Thanks [Raphaela Protásio](https://github.com/Rawphs) and [Lucas Mendonça](https://github.com/luuchowl) for the Portuguese [translation (portugues)](?lan=pt)
+
 Thanks [Nicolas Barradeau](https://twitter.com/nicoptere) and [Karim Naaji](http://karim.naaji.fr/) for the French [translation (français)](?lan=fr)
 
 Thanks [Andrea Rovescalli](https://www.earove.info) for the Italian [translation (italiano)](?lan=it)

chap-header.php

@@ -1,6 +1,6 @@
 
     <div class="header">
         <p class="subtitle"><a href="https://thebookofshaders.com/">The Book of Shaders</a> by <a href="http://patriciogonzalezvivo.com">Patricio Gonzalez Vivo</a> & <a href="http://jenlowe.net">Jen Lowe</a> </p>
-        <p> <a href="?lan=jp">日本語</a> - <a href="?lan=ch">中文版</a> - <a href="?lan=kr">한국어</a> - <a href="?lan=es">Español</a> - <a href="?lan=fr">Français</a> - <a href="?lan=it">Italiano</a> - <a href="?lan=de">Deutsch</a> - <a href="?lan=ru">Русский</a> - <a href=".">English</a></p>
+        <p> <a href="?lan=jp">日本語</a> - <a href="?lan=ch">中文版</a> - <a href="?lan=kr">한국어</a> - <a href="?lan=es">Español</a> - <a href="?lan=pt">Portugues</a> - <a href="?lan=fr">Français</a> - <a href="?lan=it">Italiano</a> - <a href="?lan=de">Deutsch</a> - <a href="?lan=ru">Русский</a> - <a href=".">English</a></p>
     </div>
     <hr>