Added failed_evaluations property to StudentProject model.
This is used to store GradingRecords which state a fail for this project. It's a list because manual changes in GradingRecords might force multiple GradingRecords to state a fail. Also it needs to be clear which GradingRecords have been processed and with which grade_decision.
Added view for editing GradingRecords.
This view shows a list of GradingRecords if the id param is not present in the GET data.
Also renamed grading_record to view_records and fixed the redirect for that page
to also point to the GradingRecord edit page.