fix(tasks): don't include undone overdue tasks from archived lists or namespaces in notification mails

Resolves vikunja/api#1324

pkg/db/fixtures/tasks.yml

@@ -337,6 +337,7 @@
   bucket_id: 20
   created: 2018-12-01 01:12:04
   updated: 2018-12-01 01:12:04
+  due_date: 2018-10-30 22:25:24
 - id: 37
   title: 'task #37'
   done: false

pkg/models/task_overdue_reminder.go

@@ -37,7 +37,9 @@ func getUndoneOverdueTasks(s *xorm.Session, now time.Time) (usersWithTasks map[i
 
 	var tasks []*Task
 	err = s.
-		Where("due_date is not null and due_date < ?", nextMinute.Add(time.Hour*14).Format(dbTimeFormat)).
+		Where("due_date is not null AND due_date < ? AND lists.is_archived = ? AND namespaces.is_archived = ?", nextMinute.Add(time.Hour*14).Format(dbTimeFormat), false, false).
+		Join("INNER", "lists", "lists.id = tasks.list_id").
+		Join("INNER", "namespaces", "lists.namespace_id = lists.id").
 		And("done = false").
 		Find(&tasks)
 	if err != nil {