title: react: app starting with localhost/appname
body: <p><a href="https://i.stack.imgur.com/1VIPo.png" rel="nofollow noreferrer">after deploy gh-pages</a> <br>
  After I deploy the my app to gh-pages, it does not start with http://localhost:3000. It starts with http://localhost:3000/appname and can not viewed in my app; local and gh pages, I can cannot see data on app on my homepage.</p>