URL in description and README broken

The URL in the repository description and 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-nshekarb4u/

更新 README 中的 URL 和仓库描述，使二者都指向 https://githubschool.github.io/github-games-nshekarb4u/。先打开 README 和仓库设置，然后验证每个显示的链接都能解析到此游戏副本。

由索引模型根据 Issue 内容生成。