new_contents: # -*- coding: utf-8 -*-
  # Generated by Django 1.11.17 on 2020-10-23 12:33
  from __future__ import unicode_literals
  
  from django.db import migrations, models
  
  
  class Migration(migrations.Migration):
  
      dependencies = [
          ('time_based', '0006_auto_20201021_1315'),
      ]
  
      operations = [
          migrations.AddField(
              model_name='ongoingactivity',
              name='start',
              field=models.DateTimeField(blank=True, null=True, verbose_name='Start of activity'),
          ),
          migrations.AddField(
              model_name='withadeadlineactivity',
              name='start',
              field=models.DateTimeField(blank=True, null=True, verbose_name='Start of activity'),
          ),
          migrations.AlterField(
              model_name='onadateactivity',
              name='start',
              field=models.DateTimeField(blank=True, null=True, verbose_name='activity date'),
          ),
          migrations.AlterField(
              model_name='ongoingactivity',
              name='duration_period',
              field=models.CharField(blank=True, choices=[('overall', 'overall'), ('day', 'per day'), ('week', 'per week'), ('month', 'per month')], max_length=20, null=True, verbose_name='duration period'),
          ),
          migrations.AlterField(
              model_name='withadeadlineactivity',
              name='duration_period',
              field=models.CharField(blank=True, choices=[('overall', 'overall'), ('day', 'per day'), ('week', 'per week'), ('month', 'per month')], max_length=20, null=True, verbose_name='duration period'),
          ),
      ]
  
subject: Add optional start of ongoing and with a deadline activities