title: Get all users which passed the exam
body: <p>I need help in django queries. 
  I have ExamResult model which keep results of exam.
  How get all users which passed the exam and are in the same study group.</p>
  
  <ol>
  <li>ExamResult model</li>
  </ol>
  
  <pre><code>
      class ExamResult(Model):
      exam = ForeignKey(Exam, blank=False, null=False, on_delete=CASCADE)
      score = IntegerField()
      user = ForeignKey('Accounts.UserAccount', blank=False, null=False, on_delete=CASCADE, )
      exam_date = DateTimeField(auto_now_add=True, blank=False, null=False)
  </code></pre>
  
  <ol start="2">
  <li>StudyGroup model</li>
  </ol>
  
  <pre><code>class StudyGroup(models.Model):
      group_name = models.CharField(max_length=10, blank=False, null=False)
  </code></pre>