use nullable for field updates

src/storage/storage.go

@@ -12,6 +12,15 @@ type Storage struct {
 	db *sql.DB
 }
 
+type Nullable[T any] struct {
+	Set   bool
+	Value *T
+}
+
+func SetNullable[T any](v *T) Nullable[T] {
+	return Nullable[T]{Set: true, Value: v}
+}
+
 func New(path string) (*Storage, error) {
 	if pos := strings.IndexRune(path, '?'); pos == -1 {
 		params := "_journal=WAL&_sync=NORMAL&_busy_timeout=5000&cache=shared"