doc: add configureStore function to store file

src/app/store.js

@@ -0,0 +1,12 @@
+import { configureStore } from '@reduxjs/toolkit';
+import { tmdbApi } from '../services/TMDB';
+import genreOrCategoryReducer from '../features/currentGenreOrCategory';
+import userReducer from '../features/auth';
+
+export default configureStore({
+    reducer: {
+        [tmdbApi.reducerPath]: tmdbApi.reducer,
+        currentGenreOrCategory: genreOrCategoryReducer,
+        user: userReducer,
+    },
+});