code: async function copy({ watch } = {}) {
    const ncp = Promise.promisify(require('ncp'));
  
    await Promise.all([
      ncp('src/public', 'build/public'),
      ncp('src/content', 'build/content'),
    ]);
  
    await fs.writeFile('./build/package.json', JSON.stringify({
      private: true,
      engines: pkg.engines,
      dependencies: pkg.dependencies,
      scripts: {
        start: 'node server.js',
      },
    }, null, 2));
  
    if (watch) {
      const watcher = await new Promise((resolve, reject) => {
        gaze('src/content/**/*.*', (err, val) => err ? reject(err) : resolve(val));
      });
      watcher.on('changed', async (file) => {
        const relPath = file.substr(path.join(__dirname, '../src/content/').length);
        await ncp(`src/content/${relPath}`, `build/content/${relPath}`);
      });
    }
  }
docs: Copies static files such as robots.txt, favicon.ico to the
  output (build) folder.