Removed broken link in free-programming-books-pt_BR.md (#5231)

* Fix Contributing.md broken link

* Fixed broken links in free-programming-books-pt_BR.md

* Removed the broken link

There is no other link found, related to the book.

books/free-programming-books-pt_BR.md

@@ -332,7 +332,6 @@
 * [Aprenda a Programar](http://www.jmonteiro.com/aprendaaprogramar/)
 * [Conhecendo Ruby - Eustaquio Rangel](https://leanpub.com/conhecendo-ruby/read)
 * [O (comovente) guia de Ruby do Why](http://why.carlosbrando.com)
-* [Ruby on Rails - Desenv. Ágil para Web com Ruby on Rails](http://www.caelum.com.br/apostila-ruby-on-rails/) - Caelum
 
 
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