title: Django - query CharFields ignoring diacritic signs
body: <p>Is there a way in Django to filter some <code>CharField</code>/<code>TextField</code> using string containing only ASCII characters but matching records in the database that may contain non-ASCII characters?</p>
  
  <p>eg. I would like below code to find a city with <code>name</code> set to Köln:</p>
  
  <pre class="lang-py prettyprint-override"><code>from django.db import models
  
  class City(models.Model):
      name = models.CharField(max_length=30)
  
  City.objects.filter(name__&lt;some lookup&gt;='koln')
  </code></pre>