koa 项目常用库：
- koa-body https://github.com/dlau/koa-body;
koa-router https://github.com/alexmingoia/koa-router;
koa-json https://github.com/koajs/json;
koa-static https://github.com/koajs/static;
koa-timeout https://github.com/wejendorp/koa-timeout;
koa-session https://npm.taobao.org/package/koa-session;持久存储，
koa-session-redis3
redis https://npm.taobao.org/package/redis; ioredis : https://npm.taobao.org/package/ioredis;推荐用这个，直接支持promise moment : http://momentjs.com/docs/日期操作的一个库 - node-bunyan 一个日志打印的模块 https://github.com/trentm/node-bunyan
- bluebird https://npm.taobao.org/package/bluebirdhttp://bluebirdjs.com/docs/getting-started.html
- co https://npm.taobao.org/package/co
- lodash http://lodashjs.com/docs/
- sequelize http://docs.sequelizejs.com/en/latest/注意，这个模块以来pg模块，专门操作postgresql数据库的node客户端
- mongoose https://npm.taobao.org/package/mongoosehttp://mongoosejs.com/
- 支持koa的mongdb orm库： http://mongorito.com/
- koa-request https://npm.taobao.org/package/koa-request
- config https://npm.taobao.org/package/config一个组织项目配置文件的的模块