Adding permalink to 404.html
Adding permalink to 404.html

Github [requires you to add](https://help.github.com/articles/creating-a-custom-404-page-for-your-github-pages-site/) `permalink: 404.html` to the YAML front matter of the 404 page. This is to display a custom 404 page instead of letting Github handle it.
Jerry-Ma/jerry-ma.github.io,Jerry-Ma/jerry-ma.github.io