Sync.m

- (void) applyOutstandingUpdates {
    __weak id this = self;
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        if(![this isUpdatePending]){
            return; //no update pending
        }
        
        NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
        NSString *documentsDirectoryPath = [documentPaths objectAtIndex:0];
        
        NSString *updatePath = [documentsDirectoryPath stringByAppendingPathComponent:@"updated.db"];
        NSString *dbPath = [documentsDirectoryPath stringByAppendingPathComponent:@"database.db"];
        
        NSFileManager *fileManager = [NSFileManager defaultManager];
        NSError *err;
        [fileManager moveItemAtPath:updatePath toPath:dbPath error:&err];
    });

}