class SystemDocument {
  generateDocumentation() {
    var document = DocumentApp.createDocument('System Documentation');
    var body = document.getBody();
    body.appendParagraph('System Overview');
    body.appendParagraph('This system receives data from Line and saves images to Google Drive and Amazon S3.');
    body.appendParagraph('Flow Diagram:');
    var plantUML = new PlantUML();
    var diagramFile = plantUML.generateFlowDiagram();
    body.appendImage(diagramFile);
  }
}