Add posts and old grade-calc

Fix small bugs
>bad commit

pages/posts/index.tsx

@@ -0,0 +1,32 @@
+import Link from 'next/link';
+import React from 'react';
+import Layout from '../../components/layout';
+import { getAllPosts } from '../../lib/slug';
+import Pages from '../../public/pages.json';
+import cachePostLinkData from '../../util/post-cache';
+
+
+function HomePage({posts}: any) {
+    Pages.sort((x, y) => { return ('' + x.title).localeCompare(y.title) });
+    return (
+        <Layout name='Posts'>
+            {posts.map((post: any) => {
+                return <section key='' className='h5 block'>
+                    <Link href={`posts/${post.slug}`}>
+                        {post.title}
+                    </Link>
+                    <div>[{ (new Date(post.last_updated)).toLocaleString()}]</div>
+                </section>
+            })}
+        </Layout>
+    )
+}
+
+export async function getStaticProps() {
+
+    return {
+        props: {posts: cachePostLinkData()}
+    };
+}
+
+export default HomePage;