code: func (u *User) DeleteSessions(db *sqlx.DB) error {
  	q := `DELETE FROM sessions WHERE userid=$1`
  	_, err := db.Exec(q, u.ID)
  	if err != nil && err != sql.ErrNoRows {
  		return err
  	}
  	return nil
  }
docs: // DeleteSessions removes any open sessions by the user. This enables "logging
  // out" of the web-based client.