title: How to serialize fields related to a model through another model?
body: <p>My models are as follows:</p>
  
  <pre><code>class Question(models.Model):
      content = models.CharField(
          max_length=1000,
          blank=False,
          default='',
          )
  
      def __str__(self):
          return self.content
  
  
  class OptionGroup(models.Model):
  
      question = models.ForeignKey(
          'Question',
          on_delete=models.CASCADE,
          default='',
          )
  
      options = models.ManyToManyField('Option')
  
  
  class Option(models.Model):
  
      content = models.CharField(
          max_length=1000,
          blank=False,
          default='',
          )
  </code></pre>
  
  <p>I am trying to create a Question serializer which will serializer Question.content and all the related Option.content without displaying any fields from OptionGroup. How do I do this?</p>