Update README.md

Author: wangbin579

README.md

@@ -56,6 +56,8 @@ If you find any errata in the book, [please open a new issue](https://github.com
 
 [High Performance MySQL](https://enhancedformysql.github.io/tech-explorer-hub/reading/database/mysql.html)
 
+[Architecture of a Database System](https://enhancedformysql.github.io/tech-explorer-hub/reading/database/database_architecture.html)
+
 ### Access the Book on GitHub Pages
 
 [Online URL](https://enhancedformysql.github.io/The-Art-of-Problem-Solving-in-Software-Engineering_How-to-Make-MySQL-Better/)