title: Django no entry in many to many table
body: <p>I have a problem with django that I really cant get my head around. Been stuck on it for two days and been looking in the source but I cant find any explanation, hopefully someone knows this better than I do!</p>
  
  <p>I have two models, <code>Publication</code> and <code>Article</code> like this</p>
  
  <pre><code>class Publication(models.Model):
      title = models.CharField(max_length=30)
      articles = models.ManyToManyField('Article',blank=True)
  
      class Meta:
          db_table = 'publications'
  
  class Article(models.Model):
      headline = models.CharField(max_length=100)
  
      class Meta:
           db_table = 'articles'
  </code></pre>
  
  <p>When I save a new <code>Publication</code> I want to automatically save a default article. I did a script to test this and it works fine. Both objects are created in their respective tables and one entry is written to the <code>publications_articles</code> table. As expected.</p>
  
  <pre><code>publication = Publication(title='The new exciting publication')
  publication.save()
  publication.articles.create(headline='The article that makes the pub so exciting')
  </code></pre>
  
  <p>However, here is the tricky part. To have the same functionality when saving a <code>Publication</code> in the admin I did override the <code>save_model()</code> function like this.</p>
  
  <pre><code>class PublicationAdmin(admin.ModelAdmin):
      list_display = ['title']
  
      def save_model(self, request, obj, form, change):
          if not change:
              obj.save()
              obj.articles.create(headline='The article that makes this pub so exciting')
          else:
              obj.save() 
  </code></pre>
  
  <p>Saving a <code>Publication</code> in the admin creates both the <code>Publication</code> and the <code>Article</code> but theres no entry in the <code>publications_articles</code> table tying them together! </p>
  
  <p>Someone please, please explain this behavior. I'm about to do a raw sql-insert just to get through with it but I want to understand why the connection between the entities is not made.</p>