public class MoveDown : MonoBehaviour {
	float posX;
	float posY;
	float speed = 0.1f;

	// Use this for initialization
	void Start () {
		posY = transform.position.y;
		posX = transform.position.x;
	}

	// Update is called once per frame
	void Update () {
		transform.position = new Vector3 (posX, posY, 0);
		posY -= speed;
	}