Method newArrow

js/Sign.js:107–110

* Create a new shield for the post. Add it to the end of the list of existing shields.

()

	 */
     
	newArrow() {
		const newArrow = new Arrow();
		this.arrows.push(newArrow);
	}
	
	deleteArrow(parentIndex,arrowIndex) {
		var selectedArrow;