add [Writing an OS in Rust] in elegant-code-base.md

en/src/elegant-code-base.md

@@ -26,6 +26,9 @@ Tutorial [`https://www.philippflenker.com/hecto/`](https://www.philippflenker.co
 ### 5. pngme book
 [This book](https://picklenerd.github.io/pngme_book/) will guide you to make a command line program that lets you hide secret messages in PNG files.  The primary goal here is to get you writing code. The secondary goal is to get you reading documentation.
 
+### 6. Writing an OS in Rust
+
+[This blog series](https://os.phil-opp.com) creates a small operating system in the Rust programming language. Each post is a small tutorial and includes all needed code, so you can follow along if you like. The source code is also available in the corresponding [Github repository](https://github.com/phil-opp/blog_os).
 
 
 **To be continued...**

zh-CN/src/elegant-code-base.md

@@ -29,5 +29,10 @@
 
 [这本书](https://picklenerd.github.io/pngme_book/) 将带领大家编写一个命令行程序，功能是在 PNG 文件中隐藏一些秘密信息，首要目标是让我们熟悉 Rust 代码。
 
+### 6. 使用 Rust 写一个小型 OS
+
+[这个博客系列](https://os.phil-opp.com) 会带领大家使用 Rust 语言创建一个小型的操作系统。其中每一篇文章都是一个小的教程并包含完整的代码。
+
+你也可以在[以下地址](https://github.com/phil-opp/blog_os)找到完整的源代码。
 
 **To be continued...**