Fixed a typo in exception name

owl/__init__.py

@@ -65,7 +65,7 @@ class OwlFlask(Flask):
             .filter_by(uid=g.uid, cid=g.course.cid)
         )
         if not enroll:
-            raise werkzeug.exceptions.Forbiden('Not enrolled in this course')
+            raise werkzeug.exceptions.Forbidden('Not enrolled in this course')
 
         g.is_teacher = enroll.is_teacher