Adds admin interface for user notifications (#357)

* Adds admin interface for user notifications

* Enable delete permissions

* pep8

keystone_api/apps/notifications/admin.py

@@ -0,0 +1,42 @@
+"""Extends the builtin Django admin interface for the parent application.
+
+Extends and customizes the site-wide administration utility with
+interfaces for managing application database constructs.
+"""
+
+from django.contrib import admin
+
+from .models import *
+
+settings.JAZZMIN_SETTINGS['icons'].update({
+    'notifications.Notification': 'fa fa-envelope',
+    'notifications.Preference': 'fas fa-mail-bulk',
+})
+
+settings.JAZZMIN_SETTINGS['order_with_respect_to'].extend([
+    'notifications.Preference',
+    'notifications.Notification',
+])
+
+
+@admin.register(Notification)
+class NotificationAdmin(admin.ModelAdmin):
+    """Admin interface for user notifications"""
+
+    list_display = ('user', 'notification_type', 'time', 'read')
+    list_filter = ('read', 'notification_type', 'time')
+    search_fields = ('user__username', 'message')
+
+    def has_change_permission(self, request, obj=None) -> False:
+        return False
+
+    def has_add_permission(self, request, obj=None) -> False:
+        return False
+
+
+@admin.register(Preference)
+class PreferenceAdmin(admin.ModelAdmin):
+    """Admin interface for user notification preferences"""
+
+    list_display = ('user',)
+    search_fields = ('user__username',)