Add storybook

src/Header.stories.jsx

@@ -0,0 +1,14 @@
+import React from "react";
+import { Header, LeftNav, RightNav } from "./Header";
+
+export default {
+  title: "Header",
+  component: Header,
+};
+
+export const Home = () => (
+  <Header>
+    <LeftNav></LeftNav>
+    <RightNav></RightNav>
+  </Header>
+);