Where to add mouse lock script?

I created a mouse lock script to lock the mouse cursor in the center of the first person controller camera… but i dont knw where to attach it. This is the script…

using UnityEngine;
using System.Collections;

public class MouseLock : MonoBehaviour {

// Update is called once per frame
void Update () {

	if (Screen.lockCursor == false) 
	{
		if(Input.GetMouseButtonDown(0))
		{
			Screen.lockCursor = true;
		}
	}
}

}

Put it in a logical place(place where you will be looking first to find it), if you say its first person controller camera, attach it to the camera.

Alternatively make an empty gameObject, name it utilities or something and put all this kind of scripts there