text: const fs = require('fs');
  const path = require('path');
  
  const appDirectory = fs.realpathSync(process.cwd());
  const resolveApp = relativePath => path.resolve(appDirectory, relativePath);
  
  const target = resolveApp('dist/index.html');
  const html404 = resolveApp('dist/404.html');
  
  if (! fs.existsSync(target)) {
    throw new Error('The file "dist/index.html" not found.');
  }
  
  const htmlContent = fs.readFileSync(target);
  
  fs.writeFileSync(html404, htmlContent);
  