extract notification repository to interface

src/repositories/InMemoryNotificationRepository.ts

@@ -0,0 +1,19 @@
+import { NotificationLookupArguments, NotificationRepository, ScheduledNotification } from "./NotificationRepository";
+
+export class InMemoryNotificationRepository implements NotificationRepository {
+  async getAllNotificationsForShuttleAndStopId(shuttleId: string, stopId: string) {
+    return [];
+  }
+
+  async getSecondsThresholdForNotificationIfExists(lookupArguments: NotificationLookupArguments) {
+    return 0;
+  }
+
+  async addOrUpdateNotification(notification: ScheduledNotification) {
+
+  }
+
+  async deleteNotificationIfExists(lookupArguments: NotificationLookupArguments) {
+
+  }
+}