npm install
npm start
If you run this and then change something in Page.js, it will not reload. Rather, it will give a
[HMR] The following modules couldn't be hot updated: (Full reload needed)
This is usually because the modules which have changed (and their parents) do not know how
to hot reload themselves.
See http://webpack.github.io/docs/hot-module-replacement-with-webpack.html for more details.
error in the console.