Improve Hacker News (pmndrs#130)

Improve README.md

Author: LuckyPigeon

examples/hacker_news/README.md

@@ -1,4 +1,10 @@
-# Explore Examples
+# Hacker News [![Open in CodeSandbox](https://img.shields.io/badge/Open%20in-CodeSandbox-blue?style=flat-square&logo=codesandbox)](https://githubbox.com/pmndrs/jotai/tree/master/examples/hacker_news)
+
+## Description
+
+Demonstrate a news articles with jotai, hit next to see more articles.
+
+## Set up locally
 
 ```bash
 git clone https://github.com/pmndrs/jotai
@@ -12,3 +18,7 @@ cd examples/hacker_news && yarn
 # start the dev server
 yarn start
 ```
+
+## Set up on codesandbox
+
+Link: https://githubbox.com/pmndrs/jotai/tree/master/examples/hacker_news