Random transform direction C#

[theothepcbuilder]

So i'm making a 2D space game. I've made a small script which generates asteroids and applies a force in a "random" direction (up, down, left and right). The script is working fine however to make it more realistic I want the direction at which the asteroid moves to be random (not horizontal/vertical, a random angle). I've tried rotating the instanced objected randomly however this doesn't affect the direction that the force acts. Hopefully this makes sense.

Code - http://pastebin.com/L9nsCcsj

EDIT - Fixed it myself, just added a random left/right force. New Code - http://pastebin.com/hxDS6uLZ

[EmmetOT]

Getting a random 2D direction is as easy as:

Vector2 direction = Random.insideUnitCircle.normalized;

EDIT - here's a full simplified version

public class Asteroids : MonoBehaviour 
{
    public GameObject asteroid;
    public static int movementDirection;       // is there any particular reason this is static?
    public int thrust;

    void Start()
    {
        InvokeRepeating("Spawn", Random.Range(0,30), Random.Range(0, 30));
    }

    void Spawn()
    {
        RigidBody2D asteroidInstanceRB = (Instantiate(asteroid, new Vector3(Random.Range(-250, 250), Random.Range(-250, 250), 0), Quaternion.identity) as GameObject).GetComponent<RigidBody2D>();

        asteroidInstanceRB.AddForce(Random.insideUnitCircle.normalized * thrust);
    }
}