Initialize Core Data stack

NATAppDelegate.m

- (void)initializeCoreDataStack
{
    // Some error checking is necessary...
    
    NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"ProjectName" withExtension:@"momd"];

    NSManagedObjectModel *managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];

    NSPersistentStoreCoordinator *persistentStoreCoordinator =
        [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:managedObjectModel];

    NSManagedObjectContext *managedObjectContext =
        [[NSManagedObjectContext alloc] initWithConcurrencyType:NSMainQueueConcurrencyType];
    [managedObjectContext setPersistentStoreCoordinator:persistentStoreCoordinator];

    self.managedObjectContext = managedObjectContext;

    dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
    dispatch_async(queue, ^{
        NSFileManager *defaultFileManager = [NSFileManager defaultManager];
        NSURL *applicationDocumentDirectoryURL =
            [[defaultFileManager URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
        NSURL *storeURL = [applicationDocumentDirectoryURL URLByAppendingPathComponent:@"ProjectName.sqlite"];

        NSError *error = nil;
        NSPersistentStore *store = [persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType
                                                                            configuration:nil
                                                                                      URL:storeURL
                                                                                  options:nil
                                                                                    error:&error];
        if (!store) {
            // ...
        }

        dispatch_sync(dispatch_get_main_queue(), ^{
            // update the UI
        });
    });
}