Add Ultimate Tic Tac Toe (#183)

README.md

@@ -852,6 +852,7 @@ Clients for commercial social platforms that had their API access cut off in a w
 
 - [Chess Clock](https://flathub.org/apps/com.clarahobbs.chessclock) - Timer for over-the-board chess games `#python` `#libadwaita`.
 - [Mahjongg](https://gitlab.gnome.org/GNOME/gnome-mahjongg) - Solitaire (one player) version of the classic Eastern tile game, Mahjongg `#gnome` `#vala` `#libadwaita`.
+- [Ultimate Tic Tac Toe](https://github.com/Nokse22/ultimate-tic-tac-toe) - [Ultimate Tic Tac Toe](https://en.wikipedia.org/wiki/Ultimate_tic-tac-toe) to play with friends or against an AI `#python` `#libadwaita`.
 
 ### Puzzles