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-jjwillich

更新 repository 描述和 README 中的 URL，使两者都指向 https://githubschool.github.io/github-games-jjwillich。验证两个链接都解析到此 repository 中的游戏副本；该 issue 明确指定了两个位置和预期的 URL。

由索引模型根据 Issue 内容生成。