react-router base href issue

Usage

1. npm install
2. npm start
3. Go to http://127.0.0.1:3000/hello

Expected results

No console errors

Actual results

2 console errors, both reading: Warning: Automatically setting basename using <base href> is deprecated and will be removed in the next major release. The semantics of <base href> are subtly different from basename. Please pass the basename explicitly in the options to createHistory