fix certificate

apps/certificate/serializers.py

@@ -2,6 +2,7 @@
 
 from rest_framework import serializers
 from apps.certificate.models import Certificate
+from apps.course.serializers import CourseDetailSerializer
 
 
 
@@ -14,7 +15,7 @@ class CertificateSerializer(serializers.ModelSerializer):
         read_only_fields = ['id', 'student', 'status', 'created_at', 'updated_at',]
 
     def get_course(self, obj):
-        return obj.course.title
+        return CourseDetailSerializer(obj.course, context=self.context).data