title: django models that contains list of another model
body: <p>I am trying to make a django model that can have a list of another model as an attribute</p>
  
  <pre><code>def author:
      name = charfield...
      list_of_books = ______________
  
  def book:
      name = charfield...
  </code></pre>
  
  <p>I want an author to be able to have a list of books he has written. And I would like to know how I can add a book to the authors list of books. </p>
  
  <p>I have seen foreignKey, but It seems like that it only to hold one object.</p>