title: Django add prefix to AutoField
body: <p>Is there a way to create an <code>AutoField</code> in Django that always begins with a certain prefix?</p>
  
  <p>I would like to create an <code>AutoField</code> that always begin with the number 1, where the first 15 saved records would have the values <code>11, 12, 13, 14, ..., 19, 110, 111, 112, 113, 114, 115</code>.</p>