Add missing imports and models to the examples in the admin documentation

AUTHORS

@@ -343,6 +343,7 @@ answer newbie questions, and generally made Django that much better:
     David Krauth
     Kevin Kubasik <kevin@kubasik.net>
     kurtiss@meetro.com
+    Vladimir Kuzma <vladimirkuzma.ch@gmail.com>
     Denis Kuzmichyov <kuzmichyov@gmail.com>
     Panos Laganakos <panos.laganakos@gmail.com>
     Nick Lane <nick.lane.au@gmail.com>

docs/ref/contrib/admin/index.txt

@@ -108,6 +108,8 @@ The ``ModelAdmin`` is very flexible. It has several options for dealing with
 customizing the interface. All options are defined on the ``ModelAdmin``
 subclass::
 
+    from django.contrib import admin
+
     class AuthorAdmin(admin.ModelAdmin):
         date_hierarchy = 'pub_date'
 
@@ -157,6 +159,8 @@ subclass::
 
     For example, let's consider the following model::
 
+        from django.db import models
+
         class Author(models.Model):
             name = models.CharField(max_length=100)
             title = models.CharField(max_length=3)
@@ -166,6 +170,8 @@ subclass::
     and ``title`` fields, you would specify ``fields`` or ``exclude`` like
     this::
 
+        from django.contrib import admin
+
         class AuthorAdmin(admin.ModelAdmin):
             fields = ('name', 'title')
 
@@ -234,6 +240,8 @@ subclass::
     A full example, taken from the
     :class:`django.contrib.flatpages.models.FlatPage` model::
 
+        from django.contrib import admin
+
         class FlatPageAdmin(admin.ModelAdmin):
             fieldsets = (
                 (None, {
@@ -356,6 +364,10 @@ subclass::
         If your ``ModelForm`` and ``ModelAdmin`` both define an ``exclude``
         option then ``ModelAdmin`` takes precedence::
 
+            from django import forms
+            from django.contrib import admin
+            from myapp.models import Person
+
             class PersonForm(forms.ModelForm):
 
                 class Meta:
@@ -459,6 +471,9 @@ subclass::
       the same as the callable, but ``self`` in this context is the model
       instance. Here's a full model example::
 
+          from django.db import models
+          from django.contrib import admin
+
           class Person(models.Model):
               name = models.CharField(max_length=50)
               birthday = models.DateField()
@@ -494,6 +509,8 @@ subclass::
 
       Here's a full example model::
 
+          from django.db import models
+          from django.contrib import admin
           from django.utils.html import format_html
 
           class Person(models.Model):
@@ -519,6 +536,9 @@ subclass::
 
       Here's a full example model::
 
+          from django.db import models
+          from django.contrib import admin
+
           class Person(models.Model):
               first_name = models.CharField(max_length=50)
               birthday = models.DateField()
@@ -547,6 +567,8 @@ subclass::
 
       For example::
 
+        from django.db import models
+        from django.contrib import admin
         from django.utils.html import format_html
 
         class Person(models.Model):
@@ -634,13 +656,13 @@ subclass::
       ``BooleanField``, ``CharField``, ``DateField``, ``DateTimeField``,
       ``IntegerField``, ``ForeignKey`` or ``ManyToManyField``, for example::
 
-          class PersonAdmin(ModelAdmin):
+          class PersonAdmin(admin.ModelAdmin):
               list_filter = ('is_staff', 'company')
 
       Field names in ``list_filter`` can also span relations
       using the ``__`` lookup, for example::
 
-          class PersonAdmin(UserAdmin):
+          class PersonAdmin(admin.UserAdmin):
               list_filter = ('company__name',)
 
     * a class inheriting from ``django.contrib.admin.SimpleListFilter``,
@@ -650,10 +672,10 @@ subclass::
 
            from datetime import date
 
+           from django.contrib import admin
            from django.utils.translation import ugettext_lazy as _
-           from django.contrib.admin import SimpleListFilter
 
-           class DecadeBornListFilter(SimpleListFilter):
+           class DecadeBornListFilter(admin.SimpleListFilter):
                # Human-readable title which will be displayed in the
                # right admin sidebar just above the filter options.
                title = _('decade born')
@@ -689,7 +711,7 @@ subclass::
                        return queryset.filter(birthday__gte=date(1990, 1, 1),
                                                birthday__lte=date(1999, 12, 31))
 
-           class PersonAdmin(ModelAdmin):
+           class PersonAdmin(admin.ModelAdmin):
                list_filter = (DecadeBornListFilter,)
 
       .. note::
@@ -732,11 +754,9 @@ subclass::
       element is a class inheriting from
       ``django.contrib.admin.FieldListFilter``, for example::
 
-          from django.contrib.admin import BooleanFieldListFilter
+          class PersonAdmin(admin.ModelAdmin):
-
-          class PersonAdmin(ModelAdmin):
               list_filter = (
-                  ('is_staff', BooleanFieldListFilter),
+                  ('is_staff', admin.BooleanFieldListFilter),
               )
 
       .. note::
@@ -746,7 +766,7 @@ subclass::
 
     It is possible to specify a custom template for rendering a list filter::
 
-        class FilterWithCustomTemplate(SimpleListFilter):
+        class FilterWithCustomTemplate(admin.SimpleListFilter):
             template = "custom_template.html"
 
     See the default template provided by django (``admin/filter.html``) for
@@ -876,10 +896,11 @@ subclass::
     the admin interface to provide feedback on the status of the objects being
     edited, for example::
 
+        from django.contrib import admin
         from django.utils.html import format_html_join
         from django.utils.safestring import mark_safe
 
-        class PersonAdmin(ModelAdmin):
+        class PersonAdmin(admin.ModelAdmin):
             readonly_fields = ('address_report',)
 
             def address_report(self, instance):
@@ -1038,6 +1059,8 @@ templates used by the :class:`ModelAdmin` views:
 
     For example to attach ``request.user`` to the object prior to saving::
 
+        from django.contrib import admin
+
         class ArticleAdmin(admin.ModelAdmin):
             def save_model(self, request, obj, form, change):
                 obj.user = request.user
@@ -1071,7 +1094,7 @@ templates used by the :class:`ModelAdmin` views:
     is expected to return a ``list`` or ``tuple`` for ordering similar
     to the :attr:`ordering` attribute. For example::
 
-        class PersonAdmin(ModelAdmin):
+        class PersonAdmin(admin.ModelAdmin):
 
             def get_ordering(self, request):
                 if request.user.is_superuser:
@@ -1298,6 +1321,8 @@ templates used by the :class:`ModelAdmin` views:
     Returns a :class:`~django.forms.ModelForm` class for use in the ``Formset``
     on the changelist page. To use a custom form, for example::
 
+        from django import forms
+
         class MyForm(forms.ModelForm):
             pass
 
@@ -1539,6 +1564,8 @@ information.
     The admin interface has the ability to edit models on the same page as a
     parent model. These are called inlines. Suppose you have these two models::
 
+         from django.db import models
+
          class Author(models.Model):
             name = models.CharField(max_length=100)
 
@@ -1549,6 +1576,8 @@ information.
     You can edit the books authored by an author on the author page. You add
     inlines to a model by specifying them in a ``ModelAdmin.inlines``::
 
+        from django.contrib import admin
+
         class BookInline(admin.TabularInline):
             model = Book
 
@@ -1682,6 +1711,8 @@ Working with a model with two or more foreign keys to the same parent model
 It is sometimes possible to have more than one foreign key to the same model.
 Take this model for instance::
 
+    from django.db import models
+
     class Friendship(models.Model):
         to_person = models.ForeignKey(Person, related_name="friends")
         from_person = models.ForeignKey(Person, related_name="from_friends")
@@ -1690,6 +1721,9 @@ If you wanted to display an inline on the ``Person`` admin add/change pages
 you need to explicitly define the foreign key since it is unable to do so
 automatically::
 
+    from django.contrib import admin
+    from myapp.models import Friendship
+
     class FriendshipInline(admin.TabularInline):
         model = Friendship
         fk_name = "to_person"
@@ -1712,6 +1746,8 @@ widgets with inlines.
 
 Suppose we have the following models::
 
+    from django.db import models
+
     class Person(models.Model):
         name = models.CharField(max_length=128)
 
@@ -1722,6 +1758,8 @@ Suppose we have the following models::
 If you want to display many-to-many relations using an inline, you can do
 so by defining an ``InlineModelAdmin`` object for the relationship::
 
+    from django.contrib import admin
+
     class MembershipInline(admin.TabularInline):
         model = Group.members.through
 
@@ -1768,6 +1806,8 @@ However, we still want to be able to edit that information inline. Fortunately,
 this is easy to do with inline admin models. Suppose we have the following
 models::
 
+    from django.db import models
+
     class Person(models.Model):
         name = models.CharField(max_length=128)
 
@@ -1816,6 +1856,8 @@ Using generic relations as an inline
 It is possible to use an inline with generically related objects. Let's say
 you have the following models::
 
+    from django.db import models
+
     class Image(models.Model):
         image = models.ImageField(upload_to="images")
         content_type = models.ForeignKey(ContentType)