title: django form creation on init
body: <p>How can I add a field in the form init function? e.g. in the code below I want to add a profile field.</p>
  
  <pre><code>class StaffForm(forms.ModelForm):
      def __init__(self, user, *args, **kwargs):
          if user.pk == 1:
              self.fields['profile'] = forms.CharField(max_length=200)
  
          super(StaffForm, self).__init__(*args, **kwargs)
  
      class Meta:
          model = Staff
  </code></pre>
  
  <p>I know I can add it just below the class StaffForm.... line but I want this to be dynamic depending on what user is passed in so can't do it this way.</p>
  
  <p>Thanks</p>