Docker mongodb + node js。如何建立工作形象？

Question

我如何构建此图像？

在运行图像上我得到了

npm info it worked if it ends with ok
npm info using npm@2.15.5
npm info using node@v4.4.5
npm info prestart koaapp@1.0.0
npm info start koaapp@1.0.0

> koaapp@1.0.0 start /home/pwrchrd/Projects/KOAapp/test
> node server.js

connection error: { [MongoError: getaddrinfo ENOTFOUND db_1 db_1:27017]
   name: 'MongoError',
   message: 'getaddrinfo ENOTFOUND db_1 db_1:27017' }