Add meta reducers injection in the Store docs

docs/store/api.md

@@ -158,3 +158,27 @@ export const reducers: ActionReducerMap<fromFeature.State> = {
 })
 export class FeatureModule { }
 ```
+
+To inject meta reducers, use the `META_REDUCERS` injection token exported in
+the Store API and a `Provider` to register the meta reducers through dependency
+injection.
+
+```
+import { MetaReducer, META_REDUCERS } '@ngrx/store';
+import { SomeService } from './some.service';
+
+export function getMetaReducers(some: SomeService): MetaReducer[] {
+  // return array of meta reducers;
+}
+
+@NgModule({
+  providers: [
+    {
+      provide: META_REDUCERS,
+      deps: [SomeService],
+      useFactory: getMetaReducers
+    }
+  ]
+})
+export class AppModule {}
+```