URL in description and README broken

The URL in the repository description and the one in the README are pointing to githubschool's copy of the game instead of yours.

Please fix both so they point to your copy of the game at https://githubschool.github.io/github-games-madanmn

更新 repository 描述和 README，目前两者都指向 githubschool 的副本。将这些链接替换为 https://githubschool.github.io/github-games-madanmn，然后检查 repository 页面和 README，以确认两个 URL 都指向此游戏的副本。

由索引模型根据 Issue 内容生成。