text: from django.db import models, migrations
  
  
  class Migration(migrations.Migration):
  
      dependencies = [
          ('chat', '0007_auto_20170314_1422'),
      ]
  
      operations = [
          migrations.AddField(
              model_name='chat',
              name='last_modify_timestamp',
              field=models.DateTimeField(null=True),
          ),
      ]
  