udpate for http://www.waltza.com/2015/07/24/flamingpants-firebase-rxswift-and-slacktextviewcontroller/

ViewController.swift

//
//  ViewController.swift
//  flamingpants-firebase-tutorial
//
//  Created by Daniel Williams on 5/29/16.
//  Copyright © 2016 Dandom, LLC. All rights reserved.
//

import UIKit
import Firebase
import RxCocoa
import RxSwift
import SlackTextViewController
import FirebaseRxSwiftExtensions

class ViewController: SLKTextViewController {

    var messageModels: [MessageModel] = [MessageModel]()
    var isInitialLoad = true
    var name = "Daniel"
    var disposeBag = DisposeBag()
    var pressedRightButtonSubject: PublishSubject<String> = PublishSubject()
    var messagesRef: Firebase!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        self.registerPrefixesForAutoCompletion([""])
        tableView?.registerClass(MessageTableViewCell.self, forCellReuseIdentifier: MessageTableViewCell.REUSE_ID)
        tableView?.rowHeight = UITableViewAutomaticDimension
        tableView?.estimatedRowHeight = 50.0
        inverted = true
        
        let rootRef = Firebase(url: "https://YOURFIREBASEAPP.firebaseio.com/")
        messagesRef = rootRef.childByAppendingPath("messages")
        
        messagesRef.rx_observe(.ChildAdded)
            .map { snapshot in
                return MessageModel(snapshot: snapshot) }
            .subscribeNext { (messageModel: MessageModel) in
                self.messageModels.insert(messageModel, atIndex: 0)
                if self.isInitialLoad == false {
                    self.tableView?.beginUpdates()
                    self.tableView?.insertRowsAtIndexPaths([NSIndexPath(forRow: 0, inSection: 0)], withRowAnimation: .Automatic)
                    self.tableView?.endUpdates()
                }
            }
            .addDisposableTo(disposeBag)
        
        messagesRef.observeSingleEventOfType(.Value) { (snapshot: FDataSnapshot!) in
            self.tableView?.reloadData()
            self.isInitialLoad = false
        }
        
        pressedRightButtonSubject
            .flatMap { bodyText -> Observable<Firebase> in
                let name = self.name
                return self.messagesRef.childByAutoId().rx_setValue(["name": name, "body": bodyText])
            }
            .subscribeNext { (newMessageReference:Firebase) -> Void in
                print("a new message was commited to firebase.")
            }
            .addDisposableTo(disposeBag)
    
    }

    override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return messageModels.count
    }
    
    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCellWithIdentifier(MessageTableViewCell.REUSE_ID, forIndexPath: indexPath) as! MessageTableViewCell
        
        let messageModelAtIndexPath = messageModels[indexPath.row]
        
        cell.nameLabel.text = messageModelAtIndexPath.name
        cell.bodyLabel.text = messageModelAtIndexPath.body
        
        
        cell.transform = tableView.transform
        return cell
    }
    
    override func didPressRightButton(sender: AnyObject?) {
        pressedRightButtonSubject.onNext(textView.text)
        super.didPressRightButton(sender)
    }

}