-(void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText {
    if (searchText.length == 0) {
        isFiltered = NO;
    }
    else {
        isFiltered = YES;

        for (NSDictionary *dict in catalog)
        {
            NSArray *elements = [dict objectForKey: @"categoriesList"];
            for (NSDictionary *element in elements)
                if ([element[@"title"] compare:searchText options:NSCaseInsensitiveSearch range:NSMakeRange(0, [searchText length])] == NSOrderedSame)
                    [filtered addObject: element];

        }
    [table reloadData];
}