Update Forums grading to use the new getAssignment long method

- Add Gradebook and Forums to a site - Add a gradebook item with some point value - Go to forums, forum settings (the default topic is fine) and assign the gradebook item under grading - Save the settings (Ideally check the database now MFR_OPEN_FORUM_T -> DEFAULTASSIGNNAME should have the gradebook ID not a name ) - Verify that the grade item comes up in the menu when editing again. - Post to that forum as a student - Grade the student - Verify the grade is updated in the gradebook without error (Ideally check the database now MFR_MESSAGE_T -> GRADEASSIGNMENTNAME should have the gradebook ID not a name ) The best test would also verify that old forum values work, but you'd have to modify the database for this. You'd insert the name of the gradebook item in these above tables/column and verify it still functions as expected. Additionally, now you should be able to have gradebook items with the same name and also rename gradebook items and not have any problems.