implement user database deletion

- modify userdbs.models.UserDatabase.delete to perform deletion of database
  user if it has no other databases assigned
- implement userdbs.views.DeleteUserDatabase
- add URL pattern 'delete_userdatabase' to userdbs.urls
- add template userdbs/userdatabase_confirm_delete.html
- add link to 'delete_userdatabase' on hosting package detail page
- add changelog entry

gnuviechadmin/userdbs/views.py

@@ -8,6 +8,7 @@ from django.shortcuts import redirect
 from django.utils.translation import ugettext as _
 from django.views.generic.edit import (
     CreateView,
+    DeleteView,
     UpdateView,
 )
 from django.contrib import messages
@@ -62,7 +63,7 @@ class AddUserDatabase(
             _('Successfully create new {type} database {dbname} for user '
               '{dbuser}').format(
                   type=userdatabase.db_user.db_type,
-                  dbname=userdatabase.db_name, db_user=userdatabase.db_user)
+                  dbname=userdatabase.db_name, dbuser=userdatabase.db_user)
         )
         return redirect(self.get_hosting_package())
 
@@ -100,3 +101,31 @@ class ChangeDatabaseUserPassword(
               ).format(dbuser=db_user.name)
         )
         return redirect(self.get_hosting_package())
+
+
+class DeleteUserDatabase(
+    HostingPackageAndCustomerMixin, StaffOrSelfLoginRequiredMixin, DeleteView
+):
+    """
+    This view is used to delete user databases and databases users if they have
+    no more databases assigned.
+
+    """
+    model = UserDatabase
+    slug_field = 'db_name'
+    context_object_name = 'database'
+
+    def get_context_data(self, **kwargs):
+        context = super(DeleteUserDatabase, self).get_context_data(**kwargs)
+        context.update({
+            'hostingpackage': self.get_hosting_package(),
+            'customer': self.get_customer_object(),
+        })
+        return context
+
+    def get_success_url(self):
+        messages.success(
+            self.request,
+            _('Database deleted'),
+        )
+        return self.get_hosting_package().get_absolute_url()