title: Django 1.11 - is there a way to combine fields from models.Model to auth.models?
body: <p>What I aim to achieve in the end is to combine the list of <strong>all</strong> users (from auth.models) with a DateTimeField from another model (model.Model). What's the best way of doing this?</p>
  
  <p>My code:</p>
  
  <p><strong>survey/models/response.py</strong></p>
  
  <pre><code>from django.contrib.auth.models import User
  from django.db import models
  
  class Response(models.Model):
      created = models.DateTimeField(auto_now_add=True)
      user = models.ForeignKey(User, null=True, blank=True)
  </code></pre>
  
  <p>In admin.py, I can create a custom user class which lists all of the registered users' usernames like so:</p>
  
  <p><strong>survey/admin.py</strong></p>
  
  <pre><code>from django.contrib.auth.models import User
  
  admin.site.unregister(User)
  
  class UserAdmin(admin.ModelAdmin):
      list_display = ('username',)
  
  admin.site.register(User, UserAdmin)
  </code></pre>
  
  <p>Essentially I want extend <strong>UserAdmin</strong> as <em>list_display = ('username', <strong>'created'</strong>)</em> - with <em>username</em> coming from <em>auth.models</em> and <em>created</em> coming from <em>models.Model</em>.</p>
  
  <p>At the moment I can create a class in admin.py that shows me a list of all the users <em>who have submitted</em> a Response. The issue is that if you have 200 users, it is more useful to see who <em>hasn't</em> submitted from a list of all users than only listing the users who have submitted a Response.</p>