[Documentation] User access levels vs User groups (Submitty#152)

* remove notes for draft version

* user access

* notes on user access level

* edits

Author: bmcutler

_data/links.yml

@@ -116,6 +116,7 @@
         - name: v19.06.02
         - name: v.19.06.01
     - name: Database Overview
+    - name: User Access Level
     - name: Course Creation
     - name: Setting up Internal Git
       link: git

_docs/sysadmin/user_access_level.md

@@ -0,0 +1,91 @@
+---
+title: User Access Level
+category: System Administrator
+---
+
+
+### User Access Level
+
+At the system level, Submitty has 3 levels of user access.  This
+information is stored in the master `Submitty` database, `users`
+table, `user_access_level` column.
+
+* **Superuser = 1**  
+    This special category of user should be rarely
+    used, limited to system administrators.  Most capabilities of
+    superusers are still in the planning stages; for example, being
+    able to edit the user access level of other users on the system,
+    add new terms, etc.  Currently most of this functionality is only
+    available from the GNU/Linux command line.
+
+* **Faculty = 2**  
+    This category of user should be limited to faculty
+    at your institution.  Faculty users can make new courses,
+    restricted toqterms that have already been defined, and
+    limited to sharing a Linux group of one of their pre-existing
+    courses.
+
+* **User = 3**  
+    All other users -- students, teaching assistants,
+    graders, etc.
+
+When a superuser or faculty level user logs in and visits the main
+home screen for Submitty, their access level is listed in the "About
+You" box.
+
+![](/images/access_level.png)
+
+From this home screen superuser and faculty users can create new
+courses.  We plan to add other features for these users in future
+releases.
+
+
+### User Group or Role
+
+Within a specific course, a user will be a member of one of the
+following groups.
+
+* **Instructor = 1**  
+    Instructors can add students and graders to the
+    course, change the group or role of users in the course, mange 
+    registration and rotating sections, create and edit gradeables,
+    upload course materials, etc.
+
+* **Full Access Grader = 2**  
+    Full Access Graders can view and enter or change the grades of any
+    student in the course for gradeables that are open to grading by
+    full access or limited access graders, even if they are not
+    specifically assigned to that student.  This group or role is
+    useful in very large courses with large teaching staff.  For
+    example, graduate student teaching assistants who assume more
+    responsibility and occasionally substitute for each other would
+    need access to enter or modify the grades of sections assigned to
+    other graduate student teaching assistants.
+
+* **Limited Access Grader = 3**  
+    Limited Access Graders can view and enter or change the grades
+    only for students in section that they are explicitly assigned to
+    grade.  This group or role is often used for more junior members
+    of the teaching staff, for example undergraduate teaching
+    assistants with more limited responsibilities.  These students may
+    be more likely to have conflicts of interest with classmates who are friends
+    because they are closer in age or cohort to the students in the
+    class. 
+
+* **Student = 4**  
+    Finally we have the student group, who has no access to grading.
+    Note that users who are in the Student Group who are assigned to the NULL
+    registration section (indicating they have dropped the course)
+    will not be able to access the course.
+
+
+_NOTE:_ User Access Level for the system is a separate from User Group
+for each course.  Typically users with **Faculty** User Access Level
+will be in the **Instructor** Group for each of their courses, but
+this is not required.  In fact, it can be helpful to for faculty users
+to explore the Submitty interface for a specific course as a member of
+the **Student** User Group.  And sometimes it is useful to put the
+head graduate teaching assistant in the **Instructor** group for a
+large course so they can assist with course management.
+
+See also [Create or Edit Gradeable](../instructor/create_edit_gradeable#grading-user-groups).