fix generating unique ID for new items
fix generating unique ID for new items

SlovakNationalGallery/web-umenia-2,SlovakNationalGallery/web-umenia-2,SlovakNationalGallery/web-umenia-2,rastislav-chynoransky/web-umenia-2,rastislav-chynoransky/web-umenia-2,SlovakNationalGallery/web-umenia-2,rastislav-chynoransky/web-umenia-2