title: Multiple models and one serializer
body: <p>I have one main model called Profile and three with relation OneToOne to the main model(ProfileFacebook, ProfileGoogle, ProfileTwitter).</p>
  <p>I would like to create ProfileSerializer, and depending of the request it will give the correct data from specific model and table.</p>
  <pre><code>class Profile(models.Model):
      active = models.BooleanField(blank=True, null=True)
      address = models.CharField(max_length=32, null=True, blank=True)
  
      status = models.CharField(max_length=255, blank=True)
      category = models.CharField(max_length=255, blank=True)
      preferences = models.CharField(max_length=255, blank=True)
  
  
  class ProfileFacebook(models.Model):
      profile = models.OneToOneField(Profile, related_name='profile_facebook', on_delete=models.CASCADE)
      account_uid = models.CharField(max_length=50, blank=True)
      secret = models.CharField(max_length=50, blank=True)
      passphrase = models.CharField(max_length=50, blank=True)
  
  
  class ProfileGoogle(models.Model):
      profile = models.OneToOneField(Profile, related_name='profile_google', on_delete=models.CASCADE)
      account_uid = models.CharField(max_length=50, blank=True)
      secret = models.CharField(max_length=50, blank=True)
      passphrase = models.CharField(max_length=50, blank=True)
  
  
  class ProfileTwitter(models.Model):
      profile = models.OneToOneField(Profile, related_name='profile_twitter', on_delete=models.CASCADE)
      account_uid = models.CharField(max_length=50, blank=True)
      secret = models.CharField(max_length=50, blank=True)
      passphrase = models.CharField(max_length=50, blank=True)
  
  
  class ProfileSerializer(serializers.ModelSerializer):
      class Meta(BaseMeta):
          class Meta(BaseMeta):
          model = Profile
          fields = (
              'active', 'address', 'status', 'category',
              'preferences'
          )
          profile_fields = ('account_uid', 'secret', 'passphrase')
  </code></pre>