My player wont move and i dont know why

I am making this game from https://www.youtube.com/watch?v=qwuPiaFU37w this series at 32:03 i done everything right in the code but my player just wont move i upped the maxSpeed to 30 and still wont work.

using UnityEngine; using System.Collections;

public class PlayerMovement : MonoBehaviour { public float moveSpeed; private float maxSpeed = 30f;

 public Vector3 input;



 // Use this for initialization
 void Start () {
 
 }
 
 void Update () {
     input = new Vector3(Input.GetAxis ("Horizontal"), 0, Input.GetAxis ("Vertical"));
     if(rigidbody.velocity.magnitude < maxSpeed)
     {
             rigidbody.AddForce(input * moveSpeed);
     }

 }

}