Added sudoku-rs (#51)

Not sure if you have any tui-rs examples yet, decided to add my own small game. It has a few nice features like dynamically resizing UI, a timer, number counter, and highlighting for numbers that the existing Sudoku example does not have.

README.md

@@ -76,6 +76,7 @@ List of projects that provide terminal user interfaces
 - [nSnake](https://github.com/alexdantas/nSnake) The classic snake game with textual interface
 - [nudoku](https://github.com/jubalh/nudoku) ncurses based sudoku game
 - [steam-tui](https://github.com/dmadisetti/steam-tui) Just a simple TUI client for steamcmd. Allows for the graphical launching, updating, and downloading of steam games through a simple terminal client.
+- [sudoku-rs](https://github.com/MitchelPaulin/sudoku-rs) Sudoku built with tui-rs
 - [terminal-phase](https://gitlab.com/dustyweb/terminal-phase) Space shooter game that runs in your terminal!
 - [tinytetris](https://github.com/taylorconor/tinytetris) 80x23 terminal tetris!