add exam collections

rapids/models.py

@@ -28,6 +28,7 @@ from django.contrib.contenttypes.fields import GenericRelation
 from generic.models import (
     CidUser,
     CidUserGroup,
+    ExamCollection,
     ExamUserStatus,
     QuestionBase,
     Site,
@@ -648,6 +649,8 @@ class Exam(ExamBase):
 
     exam_user_status = GenericRelation(ExamUserStatus)
 
+    exam_collection = models.ForeignKey(ExamCollection, blank=True, null=True, on_delete=models.SET_NULL, related_name="rapids_exams")
+
     def get_normal_abnormal_breakdown(self):
         # Inefficient but more extendible
         questions = self.exam_questions.all()