private static string addArticulo(DBStorage db, string message)
        {
            Articulo articulo;

            try
            {
                articulo = (Articulo)JsonConvert.DeserializeObject(message, typeof(Articulo));
            }
            catch (Exception) { return("ERR"); }
            if (articulo == null || !articulo.isValid())
            {
                return("ERR");
            }

            return(db.addArticulo(articulo) ? "OK" : "ERR");
        }