title: Django Model seeking alternative to many to many fields
body: <p>I am writing an exam system, below is my model:</p>
  
  <pre><code>class Exam(models.Model):
      name = models.CharField(
          max_length=100
      )
  
  class Topic(models.Model):
      name = models.CharField(
          max_length=50
      )
  
  class Question(models.Model):
      title = models.CharField(
          max_length=100
      )
      topic = models.ForeignKey(
          Topic
      )
  
  class Choice(models.Model):
      question = models.ForeignKey(
          Question,
          on_delete=models.CASCADE
      )
      choice_text = models.CharField(
          max_length=200
      )
      is_right_answer = models.BooleanField(
          default=False
      )
  </code></pre>
  
  <p>I want when I create an exam, i can give multiple topics like <code>math</code>, <code>physics</code>, <code>business</code> etc and then i can query all the questions related that topics and show in the frontend.</p>
  
  <p>My problem only in exam creation, i am not getting should I use ManyToManyField or there is any alternative solution</p>
  
  <p>I just want to select multiple <code>topic</code> during i create an exam. Can anyone help me in this  case?</p>