Object Movement in Camera facing direction

Hi,

I'm new to Unity and right now trying to learn the basics. I have successfully created a sphere, sphere movements, a 3rd person camera, camera rotation around the sphere. The only thing is that I want the sphere to move in the direction that the camera is facing by changing the axes values according to the camera.

And I have tried many methods, so any help would be nice. Thank you.

Player Controller Code:

public class Playercontroller1 : MonoBehaviour {

 public GameObject emptyobject;
 public float speed=0;
 private Vector3 offset;
 private Rigidbody rb;

 void Start()
 {
     rb = GetComponent<Rigidbody>();
     //count = 0;
     //setcountText ();
     //win.text = "";
 }
 void Update()
 {
     float moveHorizontal = Input.GetAxis ("Horizontal");
     float moveVertical = Input.GetAxis ("Vertical");
     Vector3 movement = new Vector3 (moveHorizontal, 0.0f, moveVertical);
     rb.AddForce (movement*speed);
 }

}

using UnityEngine; using System.Collections;

Camera Controller Code:

public class cameracontroller1 : MonoBehaviour {

 public GameObject player;
 private Vector3 offset;
 private float x_rotation = 0.0f;
 private float y_rotation = 0.0f;
 
 public float x_sensitivty = 5.0f;
 public float y_sensitivty = 5.0f;
 public float speed=5;
 public Transform target;
 public Rigidbody rb;
 
 void Start () 
 {
     offset = transform.position - player.transform.position;
     rb = GetComponent<Rigidbody>();
 }
 
 // Update is called once per frame
 void Update () {
     transform.position = player.transform.position + offset;//Camera position behind ball
     x_rotation += Input.GetAxis ("Mouse X") * x_sensitivty;//Mouse input X axis
     y_rotation -= Input.GetAxis ("Mouse Y") * y_sensitivty;//Mouse input Y axis

     transform.LookAt(target);//Look at the ball
     transform.RotateAround (target.transform.position, Vector3.up, x_rotation*speed);//Rotate the camera around the ball in x axis
 }

}