Unity UI - Load scene on button click

using UnityEngine;
using System.Collections;

public class ButtonCodeThatsBeenDroppedOntoButton : MonoBehaviour
{
    public void IveBeenClicked()
    {
        //The scene you are loading should be included in the build settings
        //Example, note without the .unity on the end of the scene name
        Application.LoadLevel("Level1");
    }
}

Should add using UnityEngine.SceneManagement; at the top, and now SceneManager.LoadScene("Level1"); Thanks to the update from Unity ;p

using UnityEngine;
using System.Collections;
using UnityEngine.SceneManagement;

public class RestartLvl1 : MonoBehaviour
{
    public void IveBeenClicked()
    {
        //The scene you are loading should be included in the build settings
        //Example, note without the .unity on the end of the scene name
        SceneManager.LoadScene("Level 1");
    }
}

This should work!