Merge pull request mtdvio#711 from YurokBo/patch-1

Update README.md

Author: mr-mig

README.md

@@ -272,3 +272,4 @@ But knowing the stuff will help you become better! :muscle:*
 - :link: [Codility](https://www.codility.com/)
 - :link: [ICPC Problem Archive](https://icpc.kattis.com/)
 - :link: [Codemia](https://codemia.io/)
+- :link: [Codebattle](https://codebattle.hexlet.io/)