Update free-programming-books-zh.md
@@ -19,6 +19,7 @@
* [Udacity](https://www.udacity.com/)
* [xuetangX](https://www.xuetangx.com/)
* [Codecademy](http://www.codecademy.com/?locale_code=zh)
+* [CodeSchool](https://www.codeschool.com/)
###软件开发方法
vhf / victor felder