Drop qt_users dependency for configs and track app version

internal/localdb/converters.go

@@ -31,7 +31,7 @@ func ConfigurationToLocal(cfg *models.Configuration) *LocalConfiguration {
 		CreatedAt:        cfg.CreatedAt,
 		UpdatedAt:        time.Now(),
 		SyncStatus:       "pending",
-		OriginalUserID:   cfg.UserID,
+		OriginalUserID:   derefUint(cfg.UserID),
 		OriginalUsername: cfg.OwnerUsername,
 	}
 
@@ -60,7 +60,6 @@ func LocalToConfiguration(local *LocalConfiguration) *models.Configuration {
 
 	cfg := &models.Configuration{
 		UUID:           local.UUID,
-		UserID:         local.OriginalUserID,
 		OwnerUsername:  local.OriginalUsername,
 		Name:           local.Name,
 		Items:          items,
@@ -76,10 +75,21 @@ func LocalToConfiguration(local *LocalConfiguration) *models.Configuration {
 	if local.ServerID != nil {
 		cfg.ID = *local.ServerID
 	}
+	if local.OriginalUserID != 0 {
+		userID := local.OriginalUserID
+		cfg.UserID = &userID
+	}
 
 	return cfg
 }
 
+func derefUint(v *uint) uint {
+	if v == nil {
+		return 0
+	}
+	return *v
+}
+
 // PricelistToLocal converts models.Pricelist to LocalPricelist
 func PricelistToLocal(pl *models.Pricelist) *LocalPricelist {
 	name := pl.Notification