fix error

apps/course/admin/course.py

@@ -36,7 +36,7 @@ from utils.admin import project_admin_site
 from utils.json_editor_field import JsonEditorWidget
 from apps.course.models import Course, Glossary, Attachment, CourseCategory, Participant
 from apps.course.models.lesson import Lesson
-from apps.account.models import StudentUser
+from apps.account.models import StudentUser, User
 
 from utils.schema import get_weekly_timing_schema, get_course_feature_schema
 
@@ -218,7 +218,7 @@ from unfold.widgets import UnfoldAdminSelectWidget
 
 class AddStudentForm(forms.Form):
     student = forms.ModelChoiceField(
-        queryset=StudentUser.objects.filter(is_active=True),
+        queryset=User.objects.filter(is_active=True),
         label=_("Select Student"),
         widget=UnfoldAdminSelectWidget,  
         required=True