How do I get a ball to shoot in the direction that my player is facing

In my game a robot has to shoot a ball into a goal. My problem is that when I shoot it always shoots in the same exact direction. It wont shoot in the direction that the player is facing
I am using C#.

using UnityEngine;
using System.Collections;

class shooting : MonoBehaviour {
public float forward = 100f;
public float up = 70f;

 //Use this for initialization
void Start () {

}

// Update is called once per frame
void OnCollisionStay(Collision collision) {
	if (collision.gameObject.name == ("blue robot")){

					
					if (Input.GetKey (KeyCode.Space))
							rigidbody.AddForce (Vector3.right * forward * Time.deltaTime);
					if (Input.GetKey (KeyCode.Space))
							rigidbody.AddForce (Vector3.up * up * Time.deltaTime);

			}


}

}

It depends how you are moving your object.

If your robot is facing in the direction of the blue arrow, the forward vector, then to shot forward you need to multiply the force with the direction(i.e Vector3.Forward)

Use the transforms forward/up/right, not the world-space Vector3 forward/up/right, eg :

rigidbody.AddForce (transform.right * forward * Time.deltaTime);