[2D] Rotating a GameObject and move it in facing direction

Hey Guys, i just started experimenting with Unity and I began with a little space shooter project.
I want my GameObject to rotate around the z axis if I am pressing the left or right arrow key and I want to move it in the facing direction if I am pressing up or down arrow key.

This is my solution right now:

using UnityEngine;
using System.Collections;

public class PlayerMovement : MonoBehaviour 
{
    float InputX;
    float InputY;

	void Start () 
    {
	
	}
	
	void Update () 
    {
        InputX = Input.GetAxis("Horizontal");
        InputY = Input.GetAxis("Vertical");
	}

    void FixedUpdate()
    {
        if(InputX != 0)
        {
            transform.Rotate(-Vector3.forward * InputX);
        }

        if(InputY != 0)
        {
            transform.Translate(transform.up * InputY);
        }
    }
}

With this script i can rotate and move the player but after the Player is rotated in a direction its not moving in the facing direction.

You don’t have to write “GetComponent()” every time. Just use “transform”.

Instead of “GetComponent().up” use “transform.forward”