SLCI combine discount app

- Install shopify app dependencies like shopify-koa-auth, isomorphic-fetch, koa, and koa-router
- Create a server.js under the root project and instantiate all the dependencies
- Initialize shopify context and add an object parameters with properties from my sandbox app wih values like API keys, secret, scopes etc..
- Use ngrok for temporary host
- Authenticate the app to my sandbox shopify store for testing