public IActionResult Post()
        {
            return(BasicAuthentication.Auth("update", options.UpdatePassword, HttpContext, async() =>
            {
                var metadataBeforeUpdate = cache.GetAll().Select(vp => new VertretungsplanMetadata(vp)).ToList();
                await dataLoader.LoadDataFromS3();
                var metadataAfterUpdate = cache.GetAll().Select(vp => new VertretungsplanMetadata(vp)).ToList();

                // Only send notification if data has changed
                if (!metadataAfterUpdate.SequenceEqual(metadataBeforeUpdate))
                {
                    await notifier.NotifyFCM();
                }
            }));
        }