Add RTD tutorial

README.md

@@ -1767,6 +1767,7 @@ A registry allows you to publish your Rust libraries as crate packages, to share
   * [exercism.org](https://exercism.org/tracks/rust) — programming exercises that help you learn new concepts in Rust.
   * [Hands-on Rust](https://pragprog.com/titles/hwrust/hands-on-rust/) - A hands-on guide to learning Rust by making games - by [Herbert Wolverson](https://github.com/thebracket/) (paid)
   * [Idiomatic Rust](https://github.com/mre/idiomatic-rust) —  A peer-reviewed collection of articles/talks/repos which teach idiomatic Rust.
+  * [Learn Rust by 500 lines code](https://github.com/cuppar/rtd) — Learn Rust by 500 lines code, build a Todo Cli Application from scratch.
   * [Learning Rust With Entirely Too Many Linked Lists](https://rust-unofficial.github.io/too-many-lists/) — in-depth exploration of Rust's memory management rules, through implementing a few different types of list structures.
   * [Little Book of Rust Books](https://lborb.github.io/book/) - Curated list of rust books and how-tos.
   * [Programming Community Curated Resources for Learning Rust](https://hackr.io/tutorials/learn-rust) — A list of recommended resources voted by the programming community.