title: Django: ManyRelatedManager is not Callable
body: <p>I have a site with users who can take terms at University:</p>
  
  <pre><code>class Term(models.Model):
      school = models.ForeignKey(School)
      name = models.CharField(max_length=200)
      isPrimaryTerm = models.BooleanField()
      date = models.DateField()
  
  class MyUser(models.Model):
      user = models.ForeignKey(User, unique=True)
      takingReqSets = models.ManyToManyField(RequirementSet, blank=True)
      takingTerms = models.ManyToManyField(Term, blank=True)
      takingCourses = models.ManyToManyField(Course, through=TakingCourse, blank=True)
      school = models.ForeignKey(School)
  </code></pre>
  
  <p>When I try to add to the set of terms the user is taking, I get an error:</p>
  
  <pre><code>def add_term(request):
      curr_user = User.objects.get(id=request.GET['pk'])
      term = RequirementSet.objects.filter(pk=request.GET['term_pk']).get()
  
      curr_user.get_profile().takingTerms().add(term)
      curr_user.get_profile().save()
  </code></pre>
  
  <p>This raises a <code>TypeError</code>:</p>
  
  <p><strong>'ManyRelatedManager' object is not callable</strong></p>
  
  <p>What am I doing wrong?</p>