Add Chess Design Link

Author: Tusamma Sal Sabil

readme.md

@@ -41,7 +41,7 @@
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  <a href="object-oriented-design-case-studies/design-a-restaurant-management-system.md"><b>Design a Restaurant Management system</b></a>
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- <a href="object-oriented-design-case-studies/"><b>Design Chess</b></a>
+ <a href="object-oriented-design-case-studies/design-chess.md"><b>Design Chess</b></a>
  <br />
  <a href="object-oriented-design-case-studies/"><b>Design an Online Stock Brokerage System</b></a>
  <br />