Update README.md

Author: simran2104

Tictactoe/README.md

@@ -2,3 +2,6 @@
 <p>
 Tic-tac-toe is a fun game that you can play any time and anywhere as long as you have a piece of paper, a pencil, and an opponent. Tic-tac-toe is a zero sum game, which means that if both players are playing their best, that neither player will win.
 </p>
+<p align="center">
+  <img src="https://github.com/simran2104/Python-Projects/blob/main/Tictactoe/demo.gif">
+  </p>