add comment function

src/documents/migrations/1023_add_comments.py

@@ -0,0 +1,19 @@
+from django.db import migrations, models
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ('documents', '1016_auto_20210317_1351'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Comment',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('comment', models.TextField()),
+                ('created', models.DateTimeField(auto_now_add=True)),
+                ('document_id', models.PositiveIntegerField()),
+                ('user_id', models.PositiveIntegerField())
+            ],
+        )
+    ]