Entity with list of custom class

[tsework17]

Until embedded entities are supported, can anyone share their workaround for an entity with a nested class? I've seen TypeConverters being mentioned in some discussions but I can't seem to figure out how to use it in this case.

class Order{
  String id;
  int total;
List<Item> items;
}

class Item{
 String itemId;
 String itemDescription;
 int quantity
}

I tried using this TypeConverter

class ItemConverter
    extends TypeConverter<List<Item>, String> {
  @override
  List<Item> decode(String databaseValue) {
    final jsonFile = json.decode(databaseValue);
    List<Item> items= [];
    items= List.from(jsonFile['items'])
        .map((e) =>Item.fromMap(jsonDecode(e)))
        .toList();

    return items;
  }

  @override
  String encode(List<Item> value) {
    final data = <String, dynamic>{};
    data.addAll({'items': value});
    return json.encode(data);
  }
}

but I am still getting this error: Column type is not supported for List<Item>