Add MySQL screencast (#3125)

free-podcasts-screencasts-pt_BR.md

@@ -20,6 +20,7 @@
 
 ### Databases
 
+* [Curso de Banco de Dados MySQL](https://www.youtube.com/playlist?list=PLHz_AreHm4dkBs-795Dsgvau_ekxg8g1r) (screencast)
 * [DatabaseCast](http://databasecast.com.br) (podcast)