Add react-router-redux

Recommended reading:
http://stackoverflow.com/questions/35665724/with-react-redux-router-how-should-i-access-the-state-of-the-route?rq=1
reduxjs/redux#227 (comment)
jlongster/react-redux-universal-hot-example@e13b935?diff=split
acdlite/redux-router#172
https://github.com/acdlite/redux-rx#createconnectorselectstate-render
https://shellmonger.com/2016/03/08/react-redux-and-routing/
https://blog.risingstack.com/react-js-best-practices-for-2016/
https://github.com/reactjs/redux/tree/master/examples/real-world
http://stackoverflow.com/questions/35196873/how-to-use-react-router-redux-routeactions/37494808
http://stackoverflow.com/questions/36722584/how-to-sync-redux-state-and-url-hash-tag-params/36749963#comment61535948_36749963
https://github.com/Automattic/wp-calypso/blob/master/docs/our-approach-to-data.md#third-era-redux-global-state-tree-december-2015---present

admin/client/src/boot/index.js

@@ -23,6 +23,7 @@ import BreadcrumbsReducer from 'state/breadcrumbs/BreadcrumbsReducer';
 import TextField from 'components/TextField/TextField';
 import HiddenField from 'components/HiddenField/HiddenField';
 import GridField from 'components/GridField/GridField';
+import { syncHistoryWithStore, routerReducer } from 'react-router-redux';
 
 // Sections
 // eslint-disable-next-line no-unused-vars
@@ -32,9 +33,12 @@ function initReactRouter(store) {
   routeRegister.updateRootRoute({
     component: App,
   });
-  const history = useRouterHistory(createHistory)({
-    basename: Config.get('adminUrlBase'),
-  });
+  let history = syncHistoryWithStore(
+    useRouterHistory(createHistory)({
+      basename: Config.get('adminUrlBase'),
+    }),
+    store
+  );
   ReactDOM.render(
     <Provider store={store}>
       <ReactRouter
@@ -97,7 +101,11 @@ function appBoot() {
   injector.register('GridField', GridField);
 
   const initialState = {};
-  const rootReducer = combineReducers(reducerRegister.getAll());
+  const reducers = reducerRegister.getAll();
+  const rootReducer = combineReducers({
+    ...reducers,
+    routing: routerReducer
+  });
   const middleware = [thunkMiddleware];
 
   if (Config.get('environment') === 'dev') {

package.json

@@ -55,6 +55,7 @@
     "react-dom": "^0.14.8",
     "react-redux": "^4.4.1",
     "react-router": "^2.4.1",
+    "react-router-redux": "^4.0.5",
     "redux": "https://registry.npmjs.org/redux/-/redux-3.0.5.tgz",
     "redux-thunk": "^2.1.0",
     "tinymce": "^4.3.3",