[Add] 404 page

web/404.html

@@ -0,0 +1,13 @@
+---
+layout: default
+permalink: /404.html
+---
+
+<head>
+    <title>404</title>
+    <meta http-equiv="refresh" content="0;url=/">
+</head>
+
+<body>
+<p>If you are not redirected, <a href="/">click here</a>.</p>
+</body>