adding to main

package grade;

public class Program {

    public static void main(String [] args){

        Grade susanGrade = new Grade();
        Grade billGrade = new Grade();
        susanGrade.setGrade(89);
        susanGrade.raiseGrade();
        billGrade.setGrade(92);
        billGrade.lowerGrade();
        susanGrade.displayAllGrades();
        billGrade.displayAllGrades();


    }