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-jnijjer/

更新仓库描述和 README 中的 URL，这两处都在 issue 中列出。将链接替换为 https://githubschool.github.io/github-games-jnijjer/，并验证这两个位置都指向此游戏副本。

由索引模型根据 Issue 内容生成。