Added Clean Code Developer (#2562) (#2564)

free-programming-books-de.md

@@ -28,6 +28,7 @@
 
 ### Unabhängig von der Programmiersprache
 
+* [Clean Code Developer: Eine Initiative für mehr Professionalität in der Softwareentwicklung](http://clean-code-developer.de)
 * [IT-Handbuch für Fachinformatiker](http://openbook.rheinwerk-verlag.de/it_handbuch/)
 * [Objektorientierte Programmierung](http://openbook.rheinwerk-verlag.de/oop/)
 * [Scrum und XP im harten Projektalltag](http://www.infoq.com/resource/news/2007/06/scrum-xp-book/en/resources/ScrumAndXpFromTheTrenchesonline_German.pdf) (PDF)

free-programming-books.md

@@ -607,6 +607,7 @@
 #### Professional Development
 
 * [Apprenticeship Patterns: Guidance for the Aspiring Software Craftsman](http://chimera.labs.oreilly.com/books/1234000001813/index.html) - David H. Hoover and Adewale Oshineye
+* [Clean Code Developer: An initiative for more professionalism in software development](https://www.gitbook.com/book/ccd_school/clean-code-developer-com/details) (:construction: *in process*)
 * [Confessions of an IT Manager](http://download.red-gate.com/ebooks/DotNet/Confessions_IT_Manager.zip) *(RedGate, By Phil Factor)*
 * [Don't Just Roll the Dice](http://download.red-gate.com/ebooks/DJRTD_eBook.pdf) (PDF) *(RedGate, By Neil Davidson)*
 * [How to Do What You Love & Earn What You’re Worth as a Programmer](https://leanpub.com/dowhatyoulove/read) - Reginald Braithwaite