func (s *LogStorage) LogsCollections() ([]*storage.Collection, error) {
	var names []struct {
		Name string
	}
	conn, err := Conn()
	if err != nil {
		return nil, err
	}
	defer conn.Close()
	err = conn.Apps().Find(nil).All(&names)
	if err != nil {
		return nil, err
	}
	var colls []*storage.Collection
	for _, name := range names {
		colls = append(colls, s.Collection("logs_"+name.Name))
	}
	return colls, nil
}
func (s *LogStorage) LogsCollections() ([]*storage.Collection, error) {
	var names []struct {
		Name string
	}
	conn, err := Conn()
	if err != nil {
		return nil, err
	}
	defer conn.Close()
	err = conn.Apps().Find(nil).All(&names)
	if err != nil {
		return nil, err
	}
	var colls []*storage.Collection
	for _, name := range names {
		colls = append(colls, s.Collection("logs_"+name.Name))
	}
	return colls, nil
}
// LogsCollections returns logs collections for all apps from MongoDB.