I know that from Django 1.7 I don\'t need to use South or any other migration system, so I am just using simple command python manage.py makemigrations
One option is to declare a default value for 'new_field':
new_field = models.CharField(max_length=140, default='DEFAULT VALUE')
another option is to declare 'new_field' as a nullable field:
new_field = models.CharField(max_length=140, null=True)
If you decide to accept 'new_field' as a nullable field you may want to accept 'no input' as valid input for 'new_field'. Then you have to add the blank=True statement as well:
new_field = models.CharField(max_length=140, blank=True, null=True)
Even with null=True and/or blank=True you can add a default value if necessary:
new_field = models.CharField(max_length=140, default='DEFAULT VALUE', blank=True, null=True)