title: Django model automatically set fields
body: <p>I have a form allowing users to post an article. The article table is chained with the users table so, I need to set the user_id field based on who's writing. Normally, django form will display a drop down to allow me to select the author but that's not the case for the user.</p>
  
  <pre><code>I have the following code:
  
  if request.method == 'POST':
      ArticleForm = ArticleForm( request.POST )
      if ArticleForm.is_valid():
          article = ArticleForm.save ()
          return render( request, 'success.html' )
  else:
      ArticleForm = ArticleForm()
  
  return render( request, 'post.html', {'ArticleForm': ArticleForm} )
  </code></pre>
  
  <p>How do I set a field before validating the request which will fail in case not since certain fields are supposed to be set by the code and not based on request data?</p>