Fixes in response to Victor's comments.

lms/djangoapps/courseware/models.py

@@ -67,6 +67,8 @@ class StudentModuleHistory(models.Model):
     Student. Right now, we restrict this to problems so that the table doesn't
     explode in size."""
 
+    HISTORY_SAVING_TYPES = {'problem'}
+
     class Meta:
         get_latest_by = "created"
 
@@ -81,7 +83,7 @@ class StudentModuleHistory(models.Model):
 
     @receiver(post_save, sender=StudentModule)
     def save_history(sender, instance, **kwargs):
-        if instance.module_type == 'problem':
+        if instance.module_type in StudentModuleHistory.HISTORY_SAVING_TYPES:
             history_entry = StudentModuleHistory(student_module=instance,
                                                  version=None,
                                                  created=instance.modified,

lms/djangoapps/courseware/views.py

@@ -616,10 +616,11 @@ def submission_history(request, course_id, student_username, location):
     Right now this only works for problems because that's all 
     StudentModuleHistory records.
     """
-    # Make sure our has_access check uses the course_id, eh? or is ourself
     course = get_course_with_access(request.user, course_id, 'load')
     staff_access = has_access(request.user, course, 'staff')
 
+    # Permission Denied if they don't have staff access and are trying to see
+    # somebody else's submission history.
     if (student_username != request.user.username) and (not staff_access):
         raise PermissionDenied
 

lms/templates/courseware/submission_history.html

@@ -4,7 +4,7 @@
 % for i, entry in enumerate(history_entries):
 <hr/>
 <div>
-<b>#${len(history_entries) - i}</b>: ${entry.created} EST</br>
+<b>#${len(history_entries) - i}</b>: ${entry.created} UTC</br>
 Score: ${entry.grade} / ${entry.max_grade}
 <pre>
 ${json.dumps(json.loads(entry.state), indent=2, sort_keys=True) | h}