Move parent field from Comment to own comment types

apps/course/migrations/0017_auto_20180130_0810.py

@@ -0,0 +1,29 @@
+# Generated by Django 2.0.1 on 2018-01-30 08:10
+
+from django.db import migrations
+import django.db.models.deletion
+import mptt.fields
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('course', '0016_auto_20180129_1756'),
+    ]
+
+    operations = [
+        migrations.RemoveField(
+            model_name='comment',
+            name='parent',
+        ),
+        migrations.AddField(
+            model_name='coursecomment',
+            name='parent',
+            field=mptt.fields.TreeForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.PROTECT, related_name='children', to='course.CourseComment'),
+        ),
+        migrations.AddField(
+            model_name='lessoncomment',
+            name='parent',
+            field=mptt.fields.TreeForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.PROTECT, related_name='children', to='course.LessonComment'),
+        ),
+    ]

apps/course/models.py

@@ -121,7 +121,6 @@ class Material(models.Model):
 
 
 class Comment(MPTTModel):
-    parent = TreeForeignKey('self', null=True, blank=True, related_name='children', db_index=True, on_delete=models.PROTECT)
     author = models.ForeignKey(User, on_delete=models.PROTECT)
     content = models.TextField('Текст комментария', default='')
 
@@ -141,6 +140,7 @@ class Comment(MPTTModel):
 
 
 class CourseComment(Comment):
+    parent = TreeForeignKey('self', null=True, blank=True, related_name='children', db_index=True, on_delete=models.PROTECT)
     course = models.ForeignKey(Course, on_delete=models.CASCADE, related_name='comments')
 
     class Meta:
@@ -149,6 +149,7 @@ class CourseComment(Comment):
 
 
 class LessonComment(Comment):
+    parent = TreeForeignKey('self', null=True, blank=True, related_name='children', db_index=True, on_delete=models.PROTECT)
     lesson = models.ForeignKey(Lesson, on_delete=models.CASCADE, related_name='comments')
 
     class Meta: