text: from django.db import models
  import datetime
  import pytz
  
  class Question(models.Model):
      question_text = models.CharField(max_length=1024)
      date = models.CharField(max_length=8, unique=True)
  
      def __str__(self):
          return "Question: " + str(self.pk) + " - " + self.date + " - " + self.question_text
  
  class Response(models.Model):
      user = models.ForeignKey("users.User")
      question = models.ForeignKey("questions.Question")
      response_text = models.CharField(max_length=4096)
      created = models.DateTimeField(editable=False)
  
      # http://stackoverflow.com/questions/1737017/django-auto-now-and-auto-now-add/1737078#1737078
      def save(self, *args, **kwargs):
          ''' On save, update timestamps '''
          if not self.id:
              self.created = datetime.datetime.now(pytz.utc)
          return super(Response, self).save(*args, **kwargs)
  
      def __str__(self):
          return "Response: " + str(self.pk) + " - User: " + str(self.user.pk)
  