old_contents: from django.contrib.auth.models import User
  from django.db import models
  from model.models import Skill
  
  
  class Simulator(models.Model):
      TYPES = (
          ('t', 'time'),
          ('c', 'correctness')
      )
  
      name = models.CharField(max_length=30)
      note = models.TextField(null=True, blank=True)
      type = models.CharField(max_length=1, choices=TYPES, default='t')
  
      def __unicode__(self):
          return self.name
  
  
  class Question(models.Model):
      player = models.ForeignKey(Simulator)
      skill = models.ForeignKey(Skill)
      data = models.TextField(verbose_name="Data as JSON")
  
      def __unicode__(self):
          return self.data
  
      def as_json(self):
          return dict(
              pk=self.pk,
              data=self.data,
              simulator=self.player.name,
          )
  
  
  class Answer(models.Model):
      question = models.ForeignKey(Question)
      user = models.ForeignKey(User)
      log = models.TextField()
      solving_time = models.IntegerField()
      timestamp = models.DateTimeField(auto_now=True)
      correctly_solved = models.BooleanField(default=False)
new_contents: from django.contrib.auth.models import User
  from django.db import models
  from model.models import Skill
  
  
  class Simulator(models.Model):
      TYPES = (
          ('t', 'time'),
          ('c', 'correctness')
      )
  
      name = models.CharField(max_length=30)
      note = models.TextField(null=True, blank=True)
      type = models.CharField(max_length=1, choices=TYPES, default='t')
  
      def __unicode__(self):
          return self.name
  
  
  class Question(models.Model):
      player = models.ForeignKey(Simulator, verbose_name="Simulator")
      skill = models.ForeignKey(Skill)
      data = models.TextField(verbose_name="Data as JSON")
  
      def __unicode__(self):
          return self.data
  
      def as_json(self):
          return dict(
              pk=self.pk,
              data=self.data,
              simulator=self.player.name,
          )
  
  
  class Answer(models.Model):
      question = models.ForeignKey(Question)
      user = models.ForeignKey(User)
      log = models.TextField()
      solving_time = models.IntegerField()
      timestamp = models.DateTimeField(auto_now=True)
      correctly_solved = models.BooleanField(default=False)
subject: rename player to simulator in admin