title: Get duplicates in django
body: <p>I've this name field in my database and quite a few of the names are duplicates. I want to have them unique. I know I can set the <code>unique = True</code> but that would only help with future entries. I want to know all the current entries with duplicate names. Is there an easy way to print out all the names that are duplicate in the doctor model? </p>
  
  <pre><code>class Doctor(models.Model):
     name = models.CharField(max_length=1300)
  </code></pre>