I Need help keeping my score forever

using UnityEngine;
using UnityEngine.UI;
using System.Collections;

public class ScoreManager : MonoBehaviour
{
public static int score; // The player’s score.

Text text;                      // Reference to the Text component.


void Awake ()
{
	// Set up the reference.
	text = GetComponent <Text> ();
	
	// Reset the score.
	score = 0;
}


void Update ()
{
	// Set the displayed text to be the word "Score" followed by the score value.
	text.text = "" + score;
}

}

Check out the video on saving and persistent data in the learn section