Fix: changed relation in courses models and add serializers

courses/migrations/0008_auto_20200608_1102.py

+# Generated by Django 2.2.12 on 2020-06-08 14:02
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('auth', '0011_update_proxy_permissions'),
+        ('courses', '0007_auto_20200512_2349'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='professormessage',
+            name='classes',
+            field=models.ManyToManyField(blank=True, related_name='message_courses', to='courses.Class', verbose_name='Default Class'),
+        ),
+        migrations.AddField(
+            model_name='professormessage',
+            name='groups',
+            field=models.ManyToManyField(blank=True, help_text='The Groups that will receive this message.', related_name='message_groups', to='auth.Group', verbose_name='groups'),
+        ),
+    ]

courses/models.py

@@ -652,15 +652,13 @@ class ProfessorMessage(models.Model):
         Group,
         verbose_name=_('groups'),
         blank=True,
-        help_text=_('The Groups that can have access to this forum. If empty, there are no group restrictions.'),
-        related_name="courses",
+        help_text=_('The Groups that will receive this message.'),
+        related_name="message_groups",
     )
-    default_class = models.ManyToManyField(
+    classes = models.ManyToManyField(
         'Class',
-        models.SET_NULL,
         verbose_name=_('Default Class'),
-        related_name='default_course',
-        null=True,
+        related_name='message_courses',
         blank=True,
     )
     

courses/serializers.py

@@ -123,12 +123,13 @@ class ProfessorMessageSerializer(serializers.ModelSerializer):
     course_slug = serializers.SerializerMethodField(read_only=True)
     course_name = serializers.SerializerMethodField(read_only=True)
     is_read = serializers.SerializerMethodField(read_only=True)
-    groups = self.context['request'].data.get('groups', None)
+    groups = serializers.SerializerMethodField(read_only=True)
+    classes = serializers.SerializerMethodField(read_only=True)
 
     class Meta:
         model = ProfessorMessage
         fields = ('id', 'course', 'course_name', 'course_slug', 'professor',
-                  'users', 'subject', 'message', 'date', 'is_read')
+                  'users', 'subject', 'message', 'date', 'is_read','groups', 'classes')
 
     def get_course_slug(self, obj):
         try: