Update readme for ngrx 4.0 (#47)

* Update readme for ngrx 4.0

For some reason, we need to manually specify the type of the meta-reducers, as shown in 
ngrx/platform#170 (comment)

Fixes #45

* Fix readme for ngrx store 4.0

uses fix from #43

README.md

@@ -14,19 +14,25 @@ npm install ngrx-store-localstorage --save
 4. Invoke composed function with application reducers as an argument to `StoreModule.provideStore`.
 ```ts
 import { NgModule } from '@angular/core';
-import { StoreModule, combineReducers } from '@ngrx/store';
+import { StoreModule, ActionReducerMap, ActionReducer } from '@ngrx/store';
 import { compose } from '@ngrx/core/compose';
 import { localStorageSync } from 'ngrx-store-localstorage';
 import { todos, visibilityFilter } from './reducers';
 
+
+const reducers: ActionReducerMap<IState> = {todos, visibilityFilter};
+
+export function localStorageSyncReducer(reducer: ActionReducer<any>): ActionReducer<any> {
+  return localStorageSync({keys: ['todos']})(reducer);
+}
+const metaReducers: Array<ActionReducer<any, any>> = [localStorageSyncReducer];
+
 @NgModule({
   imports: [
     BrowserModule,
-    StoreModule.provideStore(
-        compose(
-            localStorageSync({keys: ['todos']}),
-            combineReducers
-        )({todos, visibilityFilter})
+    StoreModule.forRoot(
+        reducers,
+        {metaReducers}
     )
   ]
 })