- (void)createSampleData
{
   NSArray *peopleToAdd = 
      [NSArray arrayWithObjects:
         [NSArray arrayWithObjects:@"Bob", @"Dylan", nil],
         [NSArray arrayWithObjects:@"Piotruś", @"Pan", nil],
         [NSArray arrayWithObjects:@"Jan", @"Kowalski", nil],
      nil];

   for (NSArray *names in peopleToAdd) {
      NSManagedObject *newPerson = [NSEntityDescription
             insertNewObjectForEntityForName:@"Person"
                      inManagedObjectContext:[self managedObjectContext]];
      [newPerson setValue:[names objectAtIndex:0] forKey:@"firstName"];
      [newPerson setValue:[names objectAtIndex:1] forKey:@"lastName"];
      NSLog(@"Tworzenie %@ %@...", [names objectAtIndex:0], [names objectAtIndex:1]);
   }

   NSError *error = nil;
   if (![[self managedObjectContext] save:&error]) {
      NSLog(@"Błąd podczas zapisu managedObjectContext: %@", error);
   } else {
      NSLog(@"Pomyślnie zapisano managedObjectContext!");
   }
}

- (void)dumpDataToConsole
{
   // Ta metoda zostanie zaimplementowana później.
}
