//  ViewController.swift
//  airclass
//
//  Created by Philip Thrana Bergmann on 06/12/2017.
//  Copyright © 2017 Philip Thrana Bergmann. All rights reserved.
//

import UIKit
import Firebase
import GoogleSignIn

var currenUser: User?

class ViewController: UIViewController, UITextFieldDelegate, GIDSignInUIDelegate  {


    @IBOutlet weak var emailTextField: UITextField!
    @IBOutlet weak var passwordTextField: UITextField!
    @IBOutlet var collectionTextField: [UITextField]!

    var dbRef: DatabaseReference!

    override func viewDidLoad() {
        super.viewDidLoad()

        // Google login
        GIDSignIn.sharedInstance().uiDelegate = self
        GIDSignIn.sharedInstance().signIn()
    }

    dbRef = Database.database().reference()

        for textField in self.collectionTextField {

            textField.delegate = self

//        }
    }

func loginAction(_ sender: Any) {

    Auth.auth().signIn(withEmail: self.emailTextField.text!, password: self.passwordTextField.text!, completion: {
            (user, error) in

            if let error = error {
                print("Sign in error: (error.localizedDescription)")
                return
            }

            self.dbRef.child("usersID").child(user!.uid).child("info").setValue(["email": user!.email])

            print("user logged in: (String(describing: user?.displayName))")

            self.performSegue(withIdentifier: "SignIn", sender: nil)
        })
    }


[enter image description here][1]


  [1]: https://i.stack.imgur.com/yykfC.png