JoinFriendViewController.swift

func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return resultsArray.count
}

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "userCell", for: indexPath)

    if let userCell = cell as? UserTableViewCell {
        let uid = resultsArray[indexPath.row]
        userRef.child(uid).child("displayname").observeSingleEvent(of: .value) { (snapshot) in
            userCell.displayName.text = snapshot.value as? String
        }
    }

    return cell
}

func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    let uid = resultsArray[indexPath.row]

    delegate?.didJoinFriend(uid: uid)

    self.dismiss(animated: true, completion: nil)
}