title: django-auth-ldap default values for newly created user
body: <p>I have a Django app which has two authentication backends, an LDAP backend that has all 'internal' users and a custom backend having 'external' users. All internal users which match the LDAP group search filter should be created with <code>is_staff</code>: <code>True</code>.</p>
  
  <p>Previously, we used </p>
  
  <pre><code>AUTH_LDAP_USER_ATTR_MAP = {
      "name": "cn",
      "email": "mail",
      "is_staff": "mail",
  }
  </code></pre>
  
  <p>and this seemed to work just fine, however using Django 1.10 we now get:</p>
  
  <pre><code>django.core.exceptions.ValidationError: ["'me@example.com' value must be either True or False."]
  </code></pre>
  
  <p>I know I can search for group membership and match that to <code>is_staff</code> but basically I want <strong>all</strong> accounts for users that authenticate against LDAP automatically set to <code>is_staff</code>: <code>True</code>.</p>
  
  <p>Is there a proper way to do this? I know I can fix it after the fact by hooking into the <code>django_auth_ldap.backend.populate_user</code> signal but then the user is already created, preferably I'd want to modify the user <em>before</em> they are created.</p>