title: How to make many to one field in Django?
body: <p>I want to make simple Django project based on book - author - publication</p>
  <p>Here book has an author but author has multiple books.</p>
  <p>Second I want relationship between book and publications, like publication has multiple books but book has one publication (if book published) or book has no publication (if book is not published) how can I make model for it ?</p>
  <p>Where to use foreign key in this?</p>