With previous versions of react-router, a react-router-redux package took care of linking the router and the state, but that package was recently deprecated and replaced by connected-react-router, which we'll install. I'm mentioning this because there are many articles on the web that still show the usage of the former package; be careful:
npm install --save connected-react-router
This is half the solution; getting the package to work will (once more!) require changes in the store and in the structure of your application; let's see that.