Move towards current direction on the Z axis (2D)

Hello,

I’m making a 2D game where you turn with A and D and go forward with W. I managed to get the rotating working but I can’t find out how to move towards the direction the object is facing.

 #pragma strict
var turnright : KeyCode;
var turnleft : KeyCode;
var fwards : KeyCode;

var mspeed = 6;
function Update () {

	// rigidbody2D.velocity =new Vector2(Input.GetAxis("Horizontal") * mspeed, Input.GetAxis("Vertical") * mspeed);
	if (Input.GetKey(turnleft))
	 {
	 transform.Rotate(Vector3.forward * 1);
	 }
	 if (Input.GetKey(turnright))
	 {
	 transform.Rotate(Vector3.back * 1);
	 }
	 if (Input.GetKey(fwards))
	 {
	 
	 }
}

turnright is set to D
turnleft is set to A
fwards is set to W

How can I make my object move towards the direction it is facing with speed = mspeed?

transform.position += transform.forward * mspeed;