function Background() {
	this.img  = new Image();
	this.img.src = "data/graphics/bg.jpg";
	this.img.width = canvas.width;
	this.img.height = canvas.height;
	this.speed = 2;

	this.x = 0;

	this.update = function() {
		if (this.x < (-canvas.width)) {
			this.x = 0;
		}
		ctx.drawImage(this.img, this.x, 0);
		var x2 = this.x+canvas.width;
		ctx.drawImage(this.img, x2, 0);
		this.x -= this.speed;
	}
}