public void setMainApp(Main app) {
      this.app = app;
      
      // Add observable list data to the table
      personTable.setItems(this.app.getPersonData());
      
      mitarbeiterSave.setGraphic(new ImageView(new Image(this.app.getClass().getResourceAsStream("/resources/icons/document-save.png"))));
      mitarbeiterDelete.setGraphic(new ImageView(new Image(this.app.getClass().getResourceAsStream("/resources/icons/edit-delete.png"))));
      mitarbeiterNew.setGraphic(new ImageView(new Image(this.app.getClass().getResourceAsStream("/resources/icons/document-new.png"))));
      mitarbeiterPaper.setGraphic(new ImageView(new Image(this.app.getClass().getResourceAsStream("/resources/icons/edit-paste.png"))));
      
  }