title: Django Cannot assign "u'username'": "Message.recipient" must be a "User" instance
body: <p>why I'm getting this error? </p>
  
  <p>I don't know how to get rid of this error.
  How can i clean the form field to enable the username to be validated?</p>
  
  <p>Thanks in advance.</p>
  
  <pre><code>class InboxCompany(generic.UpdateView):
  
      model = CandidateToJob
      template_name = 'dashboard/inbox-company.html'
      form_class = ComposeMessage
  
      def get(self, *args, **kwargs):
          recipient = self.get_object(queryset=CandidateToJob.objects.select_related('candidate'))
          if recipient is not None:
              user = User.objects.get(username=recipient.candidate.user.username)
              self.initial = {'recipient': user}
          return super(InboxCompany, self).get(*args, **kwargs)
  </code></pre>
  
  <p>forms.py</p>
  
  <pre><code> class ComposeMessage(ModelForm):
      recipient = forms.CharField(
          required=True,
          widget=forms.TextInput(attrs={'class': 'form-control'})
      )
      body = forms.CharField(
          required=True,
          widget=forms.TextInput(attrs={'class': 'form-control'})
      )
  
      class Meta:
          model = Message
  </code></pre>