     
     func friendPickerDidSelectUsers(friendPickerVC: FriendPickerVC, users: [User]) {
         invited = users
+        invitedUsernames = NSMutableArray()
+        
+        for user in invited {
+            let user = user as User
+            invitedUsernames.addObject(user.username)
+        }
+        
         invitedCollection.reloadData()
     }
 }

    @IBOutlet weak var descriptionLabel: UILabel!
    @IBOutlet weak var descriptionField: UITextView!
    var invited: [User] = []

    @IBOutlet weak var invitedCollection: UICollectionView!
    var photos: [UIImage] = []

        event.startTime = startTimePicker.date
        event.endTime = endTimePicker.date
        event.photos = Photo.photosFromImages(photos)
        let invUsernames = invitedUsernames as [AnyObject] as [String]
        event.invitedUsernames = invUsernames
        
        event.createWithCompletion { (success, error) -> () in
            if success == true {
