title: add data to admin modelform inline object before saving
body: <p>In relation to the question below, how would I do this for the django admin?</p>
  
  <p><a href="https://stackoverflow.com/questions/17126983/add-data-to-modelform-object-before-saving">Add data to ModelForm object before saving</a></p>
  
  <p>Example:</p>
  
  <pre><code>class FooInlineModel(models.Model):
      bar = models.CharField()
      secret = models.CharField()
  
  
  class FooInlineForm(forms.ModelForm):
      class Meta:
          model = FooInlineModel
          exclude = ('secret',)        
  
  
  class FooInline(admin.TabularInline):
      pass
  
  
  class FooAdmin(admin.ModelAdmin):
      inlines = (FooInline,)
  </code></pre>
  
  <p>This logically triggers an IntegrityError because secret is submitted NULL, how do I manually populate the field in one of the admin methods? e.g.</p>
  
  <pre><code>class ???:
      def ???:
          obj = form.save(commit=False)
          obj.secret = 'stackoverflow'
          obj.save()
  </code></pre>