Use youpin-api.js client

[rapee]

This app currently implements use raw RESTful service call to interact with YouPin API.
Instead, it should use API client (youpin-api.js) provided by youpin-city/youpin-bot.

[supasate]

I think we should create new repos for API wrappers like youpin-city/nodejs-sdk, youpin-city/php-sdk, etc.

@tvirot could you separate your youpin-api.js into youpin-city/nodejs-sdk?

[rapee]

That's good! I suggest youpin-city/youpin-node instead of nodejs-sdk so can tell what project just from the repo name.

For node.js, we can add dependency directly from git repo:

"dependencies": {
  "youpin": "youpin-city/youpin-node",
}