Add Build Your Own Redis with C/C++ (#9251)

Co-authored-by: root <root@localhost>

books/free-programming-books-langs.md

@@ -439,6 +439,7 @@ That section got so big, we decided to split it into its own file, the [BY SUBJE
 * [Beej's Guide to C Programming](http://beej.us/guide/bgc/) - Brian "Beej Jorgensen" Hall (HTML, PDF)
 * [Beej's Guide to the GNU Debugger (GDB)](http://beej.us/guide/bggdb/) - Brian "Beej Jorgensen" Hall (HTML)
 * [Build Your Own Lisp](http://www.buildyourownlisp.com) - Daniel Holden
+* [Build Your Own Redis with C/C++](https://build-your-own.org) - build-your-own.org (HTML) (:construction: *in process*)
 * [C Elements of Style](http://www.oualline.com/books.free/style/) - Steve Oualline
 * [C for Python Programmers](http://www.cburch.com/books/cpy/) - Carl Burch
 * [C Handbook](https://thevalleyofcode.com/c/) - Flavio Copes (HTML, PDF)