add Modify(String ID) to GradeSystem
commit
commit
Merge branch 'master' of https://github.com/greg65236592/AgileProject

Conflicts:
	AgileProject/bin/GradeSystems.class
	AgileProject/bin/Main.class
	AgileProject/bin/TestGradeSystems.class
	AgileProject/bin/TestUI.class
	AgileProject/bin/UI.class