title: Change field name in django admin
body: <p>I am customizing django admin and I would like to change the display name of my fields.
  I think the answer is <a href="https://docs.djangoproject.com/en/dev/ref/contrib/admin/" rel="noreferrer">here</a> but I can't find it.
  I already change the table name thanks to Meta class. I have also ordered fields, gathered them, collapsed them...</p>