add sub git and git-tools

lib/getPosts.tsx

@@ -0,0 +1,41 @@
+import { exec } from 'child_process';
+
+export type Post = {
+  title: string;
+  message?: string;
+  author: {
+    email: string;
+    name: string;
+  };
+  time: number;
+};
+
+const posts: Post[] = [
+  {
+    author: 'kjuulh',
+    post: 'some post\n',
+  },
+  {
+    author: 'kjuulh',
+    post: `some other post with
+    some more text`,
+  },
+];
+
+export const getPosts = async (): Promise<Post[]> => {
+  return new Promise((resolve, reject) => {
+    exec(`git-log --path ${process.env.POSTS_DIR}`, (error, stdout, stderr) => {
+      if (error) {
+        console.warn(error);
+        reject('could not load posts stderr: ' + stderr + 'stdout: ' + stdout);
+        return;
+      }
+
+      const posts: Post[] = JSON.parse(stdout);
+
+      resolve(posts);
+    });
+  });
+};
+
+export const revalidate = 5;