Update README.md

Author: swsoyee

README.md

@@ -26,6 +26,6 @@ My solutions of [PRACTICE PYTHON](http://www.practicepython.org/)
 [23.  
 [24. Draw A Game Board](http://www.practicepython.org/exercise/2014/12/27/24-draw-a-game-board.html)  
 [25.  
-[26.  
+[26. Check Tic Tac Toe](http://www.practicepython.org/exercise/2015/11/16/26-check-tic-tac-toe.html)  
 [27.  
 [28 . Max Of Three](http://www.practicepython.org/exercise/2016/03/27/28-max-of-three.html)