Specification for a 4th user role

[ning-y]

From today's meeting, there needs to be one more role value for the graduate student. Overall, there will be 4 roles, corresponding to:

1. Site administrators, which corresponds to the module's two professors. Site administrators should be able to access all assessments
2. Graduate students, who are responsible for manual marking of assessments. Graduate students should be able to access only assessments belonging to students assigned to them
3. Avengers/TAs, who will be able to access only assessments belonging to their studio group
4. Students

Implementation-wise, it is possible to give graduate students an identical 'role' value as avengers/TAs. The difference being only the students they are assigned---graduate students are assigned (associated) all the students they are responsible for grading, and avengers/TAs are assigned (associated) the students in their studio group.

More importantly, we need to take note that the information about these groupings will come from IVLE groups. Therefore, a process of parsing IVLE 'group' information into the backend database, as well as a way to update these relationships (as in, to update per fixed amount of time, or on student login, or on graduate student/avenger login) should be implemented.

[indocomsoft]

So we are sure that all of them has an associated IVLE account, correct?

Since we removed email+password authentication method in #48

[ning-y]

Yep, if they do not have IVLE accounts already we can just sign them up with guest accounts.

[indocomsoft]

Related to #60

[martin-henz]

I think we solved this one by giving every Avenger the right to grade every mission. Seemed to work. Any objections to this?