new_contents: from django.contrib.auth.models import User
  from django.db import models
  from django.utils.translation import ugettext_lazy as _
  
  from settings import COUPON_TYPES
  
  
  class Coupon(models.Model):
      value = models.IntegerField(_("Value"), help_text=_("Arbitrary coupon value"))
      code = models.CharField(_("Code"), max_length=30, unique=True)
      type = models.CharField(_("Type"), max_length=20, choices=COUPON_TYPES)
      user = models.ForeignKey(User, verbose_name=_("User"), null=True, blank=True,
          help_text=_("You may specify a user youn with to limit this coupon to"))
      created_at = models.DateTimeField(_("Created at"), auto_now_add=True)
      redeemed_at = models.DateTimeField(_("Created at"), blank=True, null=True)
  
      class Meta:
          ordering = ['created_at']
          verbose_name = _("Coupon")
          verbose_name_plural = _("Coupons")
  
      def __unicode__(self):
          return self.code
  
  
subject: add Coupon model