title: how to make email field required in the django user admin
body: <p>I want to make the email field required in the user admin add and
  change pages. I read this post: <a href="https://stackoverflow.com/questions/5493096/django-user-model-email-field-how-to-make-it-mandatory">Django User model email field: how to make it mandatory</a> and I did this:</p>
  
  <pre><code>class MyUserCreationForm(UserCreationForm):
      def __init__(self, *args, **kwargs):
          super(MyUserCreationForm, self).__init__(*args, **kwargs)
          # make user email field required
          self.fields['email'].required = True
  
  class UserAdmin(BaseUserAdmin):
      form = MyUserCreationForm
      add_form = MyUserCreationForm
      add_fieldsets = ((None, {'fields': ('username', 'email',
  'password1', 'password2'), 'classes': ('wide',)}),)
  
  admin.site.unregister(User)
  admin.site.register(User, UserAdmin)
  </code></pre>
  
  <p>This works fine in add user, but in change user I get the user's
  encrypted password shown in the password field, instead of what you
  normally see:</p>
  
  <pre><code>algorithm: pbkdf2_sha256 iterations: 24000 salt: ****** hash:
  **************************************
  Raw passwords are not stored, so there is no way to see this user's
  password, but you can change the password using this form.
  </code></pre>
  
  <p>And when I try to save from the change screen it says "Please correct
  the errors below." even though there are no errors shown.</p>
  
  <p>How can I fix these issues in the change form?</p>