old_contents: from django.db import models
  
  class Snap(models.Model):
      filename = models.CharField()
      downloaded = models.DateTimeField('date downloaded')
  
  
new_contents: from django.db import models
  
  class Snap(models.Model):
      filename = models.CharField('124')
      downloaded = models.DateTimeField('date downloaded')
  
  
subject: Add length to filename field