docs: function addPackageFile (devDependency = false, extraOptions = null) {
      var packageJSON = {
        name: 'app',
        description: 'Vue Build Application',
        version: '0.1.0',
        dependencies: {
          'vue-build': '^' + require('../package').version
        }
      }
  
      if (devDependency) {
        packageJSON.devDependencies = {
          'vue-build': packageJSON.dependencies['vue-build']
        }
        delete packageJSON.dependencies['vue-build']
      }
  
      if (extraOptions) {
        packageJSON = Object.assign({}, packageJSON, extraOptions)
      }
  
      fs.writeFileSync(
        path.join(projectRoot, 'package.json'),
        JSON.stringify(packageJSON, null, 2)
      )
    }