title: Restart button doesn't work on Unity 5.6
body: <p>I'm trying to make a restart button on top of a game over screen. But it seems that the button doesn't work. I've put it on the <code>On Click()</code> menu and it kept doing nothing when i clicked on it.
  My code:</p>
  
  <pre><code>using System.Collections;
  using UnityEngine;
  using UnityEngine.SceneManagement;
  
  public class ButtonCodes:MonoBehaviour
  {
      public void RestartGame()
      {
         SceneManager.LoadScene(0);
      }
  }
  </code></pre>