Sphere AI problem

Hi,
I created enemy sphere (a ball) that follows my player hit it or touch it and player dead or decreased power.
but i can’t able to script it properly. I use this code in my Sphere(Ball Enemy to gave it AI) But it does not rotate & i didn’t know how to add rotate line or something in my code) can you please help me .
I need real-time rotation when it’s following my player . With this script the enemy does not rotates it follows up my player just track or drag like . it does not rotating like the ball walking . Please help me .
here in c# . Here is my video with my problem … Golden ball is mine and the other rocks grey enemy following me without spinning - - YouTube

using UnityEngine;
 using System.Collections;
 public class EnemyAI: MonoBehaviour {
 public Transform target;
 public int moveSpeed;
 public int rotationSpeed;
 private Transform myTransform;
 void Awake(){
 myTransform = transform;
 }
 // Use this for initialization
 void Start () {
 GameObject go = GameObject.FindGameObjectWithTag("Player");
 target = go.transform;
 }
 // Update is called once per frame
 void Update () {
 Debug.DrawLine(target.position, myTransform.position, Color.cyan);
 //look at target
 myTransform.rotation = Quaternion.Slerp(myTransform.rotation, Quaternion.LookRotation(target.position - myTransform.position), rotationSpeed * Time.deltaTime);
 //move towards target
 myTransform.position += myTransform.forward * moveSpeed * Time.deltaTime;
 }
 }

Well with the current code I don’t think the following ball will rotate, but you can make it rotate by adding custom rotations using
transform.rotate().
You can find more of its details here