code: func (db *DB) Delete(doc *Doc) error {
  	if doc.ID == 0 {
  		return fmt.Errorf("doc never written")
  	}
  
  	tx, err := db.meta.Begin()
  	if err != nil {
  		return err
  	}
  	defer tx.Rollback() // no-op after Commit
  
  	if err := db.store.Delete(tx, doc); err != nil {
  		return err
  	}
  	txt := text{ID: doc.ID}
  	if err := db.store.Delete(tx, &txt); err != nil {
  		return err
  	}
  
  	err = tx.Commit()
  	if err != nil {
  		return err
  	}
  
  	return nil
  }
docs: // Delete deletes the document (or any document with the same doc.ID)
  // from the database.