title: Why is UbiquityContainer nil if user not logged into iCloud?
body: <p>I would like to use the UbiquityContainer in order to have an iCloud backup of the coredata.  However if I am not logged into the iCloud on the simulator the <code>ubContainer</code> below remains nil. </p>
  
  <pre><code>-(void)addSqliteStoreToPersistentStoreCoordinator:(NSPersistentStoreCoordinator *)psc{
      NSError *error = nil;
      NSFileManager *fm = [NSFileManager defaultManager];
      NSURL *ubContainer = [fm URLForUbiquityContainerIdentifier:nil]; // Why nil???????
      NSURL *storeURL = [ubContainer URLByAppendingPathComponent:@"f11Remote.sqlite"];
      NSMutableDictionary *options = [NSMutableDictionary dictionary];
      [options setObject:[NSNumber numberWithBool:YES] forKey:NSMigratePersistentStoresAutomaticallyOption];
      [options setObject:[NSNumber numberWithBool:YES] forKey:NSInferMappingModelAutomaticallyOption];
      [options setObject:[NSDictionary dictionaryWithObjectsAndKeys:@"FULL", @"synchronous", nil] forKey:NSSQLitePragmasOption];
      [options setObject:@"f11iCloudStore" forKey:NSPersistentStoreUbiquitousContentNameKey];
      [options setValue:ubContainer forKey:NSPersistentStoreUbiquitousContentURLKey];
      sqliteStore = [psc addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:options error:&amp;error];
      if (!sqliteStore)
          [NSException raise:@"FTDatastore: Couldn't open the local SQLite database." format:@"Reason: %@", [error localizedDescription]];
  }
  </code></pre>
  
  <p>I was expecting an <code>offline</code> version of it to work in the meanwhile and behave like core data, until the user logs into the iCloud.  What can be done?</p>