new_contents: from django.core.urlresolvers import reverse
  from django.db import models
  from jsonfield import JSONField
  
  
  class Room(models.Model):
      name = models.CharField(max_length=100)
      location = models.CharField(max_length=255, null=True, blank=True)
      desc = models.TextField(null=True, blank=True)
  
      def get_absolute_url(self):
          return reverse('room', args=[self.id])
  
      def __unicode__(self):
          return self.name
  
  
  class ProgramDate(models.Model):
      day = models.DateField()
  
      def __unicode__(self):
          return self.day.strftime("%m/%d (%a)")
  
  
  class ProgramTime(models.Model):
      begin = models.TimeField()
      end = models.TimeField()
  
      def __unicode__(self):
          return '%s - %s' % (self.begin, self.end)
  
  
  class SponsorLevel(models.Model):
      name = models.CharField(max_length=100, db_index=True)
      desc = models.TextField(null=True, blank=True)
  
      def __unicode__(self):
          return self.name
  
  
  class Sponsor(models.Model):
      slug = models.CharField(max_length=100, db_index=True)
      name = models.CharField(max_length=100, db_index=True)
      image = models.ImageField(upload_to='sponsor', null=True, blank=True)
      url = models.CharField(max_length=255, null=True, blank=True)
      desc = models.TextField(null=True, blank=True)
  
      def get_absolute_url(self):
          return reverse('sponsor', args=[self.slug])
  
      def __unicode__(self):
          return self.name
  
  
  class Speaker(models.Model):
      slug = models.CharField(max_length=100, db_index=True)
      name = models.CharField(max_length=100, db_index=True)
      image = models.ImageField(upload_to='sponsor', null=True, blank=True)
      desc = models.TextField(null=True, blank=True)
      info = JSONField()
  
      def get_absolute_url(self):
          return reverse('speaker', args=[self.slug])
  
      def __unicode__(self):
          return '%s(%s)' % (self.name, self.slug)
  
  
  class Program(models.Model):
      name = models.CharField(max_length=100, db_index=True)
      desc = models.TextField(null=True, blank=True)
      slide_url = models.CharField(max_length=255, null=True, blank=True)
      speakers = models.ManyToManyField(Speaker, blank=True)
  
      room = models.ForeignKey(Room)
      date = models.ForeignKey(ProgramDate)
      times = models.ManyToManyField(ProgramTime)
  
      def get_absolute_url(self):
          return reverse('program', args=[self.id])
  
      def begin_time(self):
          return self.times.all()[0].begin.strftime("%H:%M")
  
      def get_times(self):
          times = self.times.all()
          return '%s - %s' % (times[0].begin.strftime("%H:%M"),
                              times[len(times) - 1].end.strftime("%H:%M"))
  
      def __unicode__(self):
          return self.name
  
subject: Add default models