/**
   * Create a ChangeAcceptanceCriteria command for changing the text of an AC
   *
   * @param story Story that contains the AC
   * @param ac AC to be changed
   * @param text String to change the AC text to
   */
  public ChangeAcceptanceCriteria(Story story, AcceptanceCriteria ac, String text) {
    this.story = story;
    this.ac = ac;
    this.newText = text;

    this.oldText = ac.getText();
  }
 /** Redo the action, setting the AC text to the new text */
 @Override
 public void redo() {
   ac.setText(newText);
 }
 /** Undo the action, setting the AC text to the old text */
 @Override
 public void undo() {
   ac.setText(oldText);
 }