Restarting a Level now that Application.LoadLevel is Obsolete

Since the only answer for my question is from Unity 4 it's not sufficient. What I need is a Current line for the code i have to make my game Restart when I press the R button. There is another problem my " Press R to restart " text is not showing up in the game after i blow myself up. Here's the Code, i have several Other Scripts too that this one Calls out to.

 using UnityEngine;
 using UnityEngine.SceneManagement;
 using System.Collections;
 
 public class GameController : MonoBehaviour {
 
     public GameObject hazard;
     public Vector3 spawnValues;
     public int hazardCount;
     public float spawnWait;
     public float startWait;
     public float waveWait;
 
     public GUIText scoreText;
     public GUIText restartText;
     public GUIText gameOverText;
 
     private bool gameOver;
     private bool restart;
     private int score;
 
     void Update ()
     {
         if (restart) 
         {
             if (Input.GetKeyDown (KeyCode.R)) 
             {
                 SceneManager.LoadScene(SceneManager.GetActiveScene().name);
             }
         }
     }
 
     void Start()
     {
         gameOver = false;
         restart = false;
         gameOverText.text = "";
         restartText.text = "";
         StartCoroutine (SpawnWaves ());
         score = 0;
         UpdateScore ();
     }
 
     IEnumerator SpawnWaves()
     {
         yield return new WaitForSeconds (startWait);
         while (true) 
         {
             for (int i = 0; i < hazardCount; i++) {
                 Vector3 spawnPosition = new Vector3 (Random.Range (-spawnValues.x, spawnValues.x), spawnValues.y, spawnValues.z);
                 Quaternion spawnRotation = Quaternion.identity;
                 Instantiate (hazard, spawnPosition, spawnRotation);
                 yield return new WaitForSeconds (spawnWait);
             }
             yield return new WaitForSeconds (waveWait);
 
             if (gameOver == true) 
             {
                 restartText.text = "Press 'R' to Restart";
                 restart = true;
                 break;
             }
         }
     }
 
     public void AddScore (int newScoreValue)
     {
         score += newScoreValue;
             UpdateScore();
     }
 
     void UpdateScore ()
     {
         scoreText.text = "Score: " + score;
     }
 
     public void GameOver ()
     {
         gameOverText.text = "Game Over ";
         gameOver = true;
     }
 }