see for references: https://docs.google.com/document/d/1e56HG5gdqGL0GbU_XECSRwnVLhyfThydvFJvtKaqpdI/edit
MVP1 plan: https://docs.google.com/document/d/1US6ltclIR7CS5XJT29TUvk9M8iOQeF2S7qbYedwK134/edit
├── app.js // main entry
├── config // The configuration of my applications (logger, global config, ...)
├── models // The model data (e.g. cassandra model)
├── public // The public directory (client-side code)
├── routes // The route definitions and implementations
├── libs // The standalone services (Database service, Email service, ...)
└── views // The view rendered by the server to the client (e.g. Jade, EJS, ...)