title: django form resubmitted upon refresh
body: <p>After I submit the form for the first time and then refresh the form it gets resubmitted and and I don't want that.</p>
  
  <p>Here's my form in template :</p>
  
  <pre><code>&lt;form action = "" method = "POST"&gt; {% csrf_token %}
      {{ form.as_p }}
      &lt;input type = "submit" value = "Shout!"/&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>How can I fix this ?</p>
  
  <p>Here's my views:</p>
  
  <pre><code>def index(request):
      shouts = Shout.objects.all()
  
      if request.method == "POST":
          form = GuestBookForm(request.POST)
          if form.is_valid():
              cd = form.cleaned_data
              shout = Shout(author = cd['author'], message = cd['message'])
              shout.save()
              form = GuestBookForm()
      else:
          form = GuestBookForm()
  
      return render_to_response('guestbook/index.html', {'shouts' : shouts,
                                               'form' : form },
                                context_instance = RequestContext(request))
  </code></pre>