Add local storage

frontend/allowance-planner-v2/src/app/app.module.ts

@@ -3,13 +3,23 @@ import { BrowserModule } from '@angular/platform-browser';
 import { RouteReuseStrategy } from '@angular/router';
 
 import { IonicModule, IonicRouteStrategy } from '@ionic/angular';
+import { Drivers, Storage } from '@ionic/storage';
+import { IonicStorageModule } from '@ionic/storage-angular';
 
 import { AppRoutingModule } from './app-routing.module';
 import { AppComponent } from './app.component';
 
 @NgModule({
   declarations: [AppComponent],
-  imports: [BrowserModule, IonicModule.forRoot(), AppRoutingModule],
+  imports: [
+    BrowserModule,
+    IonicModule.forRoot(),
+    AppRoutingModule,
+    IonicStorageModule.forRoot({
+      name: '__mydb',
+      driverOrder: [Drivers.IndexedDB, Drivers.LocalStorage]
+    })
+  ],
   providers: [{ provide: RouteReuseStrategy, useClass: IonicRouteStrategy }],
   bootstrap: [AppComponent],
 })