Added more validations to attributes.
Fixed bug that would throw exception when checking for a specific error case.
Added more validations to Course attributes.
Added grade validations to Grade model.
Added gradeType attribute to Course model.
Fixed syntax error in Course model.
Abstracted "incomplete" grade to a boolean.
Updating a course now checks for compatability between the course's gradeType and the grade's value.
All students in a course must have a grade before submitting the course as finalized.
Students now have first and last names.
Added department attribute to Course model.
Added Department model.
Added "W" as a possible grade.
Course view and controller (admin included) can now handle multiple types of grades.
Professors can no longer edit grades after submitting as final.
Added more translations. Made default language Spanish.