corrected index

free-programming-books-de.md

@@ -1,15 +1,18 @@
 ###Index
 * [Android](#android)
 * [C](#c)
-* [C#](#c-sharp)
 * [C++](#c-1)
+* [C#](#c-sharp)
 * [iOS](#ios)
+* [Groovy](#groovy)
 * [Java](#java)
 * [Javascript](#javascript)
+* [PHP](#php)
 * [Python](#python)
 * [Ruby on Rails](#ruby-on-rails)
 * [Scilab](#scilab)
 * [UML](#uml)
+* [Unix](#unix)
 * [Visual Basic](#visual-basic)
 
 ###Android