title: colorful.core.ColorfulError: the color "default" is unknown. Use a color in your color palette (by default: X11 rgb.txt)
body: <p>I installed the <code>colorful</code> into my django project and I added it to installed_apps in <code>settings.py</code></p>
  
  <p>I added an <code>RGBColorField</code> to my modal. </p>
  
  <p>When I do <code>python manage.py makemigrations</code>
  I get the following error: <code>colorful.core.ColorfulError: the color "default" is unknown. Use a color in your color palette (by default: X11 rgb.txt)
  </code></p>
  
  <p>my modals.py </p>
  
  <pre><code>  from __future__ import unicode_literals
    from colorful.fields import RGBColorField
    from django.db import models
  
    class Party(models.Model):
      name = models.CharField(max_length=100)
      color = RGBColorField(default="#0000")
  </code></pre>
  
  <p>I also tried with     <code>color = RGBColorField("#0000")</code> and  <code>color = RGBColorField()</code>  and <code>color = RGBColorField(default="#000")</code> with valid color tags but always the same error</p>
  
  <p>Any help? any ideas?</p>