title: Add a ModelChoiceSet to an inlineformset after it's generated
body: <p>I have an inlineformset based off a very simple Model form.  I'd like a way to add a choiceset to one of the fields of the form, but I want to do it from the views.py file as the choiceset is generated dynamically.  Is this possible?  Python2.7, Django1.5</p>
  
  <p>models.py</p>
  
  <pre><code>class RoleForm(ModelForm):
      class Meta:
          model = Role
          fields = ['role_type', 'user', 'item']
  </code></pre>
  
  <p>views.py</p>
  
  <pre><code>def new(request):
      ''' Create a new application '''
      user = request.user
      associatedRoleTypes = getAssociatedRoleTypes(Application) 
      #^^^this returns a queryset, and is what I want model_choices to be equal to
      RoleFormSetFactory = inlineformset_factory(Application, Role, can_delete=False, form=RoleForm)
      if request.method == 'POST':
          applicationForm = ApplicationForm(request.POST)
          if applicationForm.is_valid():
              new_application = applicationForm.save()
              roleInlineFormSet = RoleFormSetFactory(request.POST, instance = new_application)
              if roleInlineFormSet.is_valid():
                  roleInlineFormSet.save()
              else:
                  print roleInlineFormSet.errors
              return redirect(reverse('index'))
      else:
  
          applicationForm = ApplicationForm()
          roleInlineFormSet = RoleFormSetFactory()
      return render(request, 'who/editapp.html',
          {'roleInlineFormSet': roleInlineFormSet,
           'applicationForm': applicationForm
           })
  </code></pre>