title: Calling a function in Django after saving a model
body: <p>Context: I'm making a blog. This blog stores information on articles in a database via a Django model. I have a FileField in said model that takes an archive of all the assets that go with this file. I add articles through the admin site.</p>
  
  <p>I want to call a function that unpacks this file immediately after the the object is saved to the model. Where would I write this function?</p>