Refactoring authentication: encapsulate jwt, jsontoken to secret.js
add SocketService (socket io)
include SocketService and socketio
new function 'getLink()'
Refactoring Authentication with ./route/secret.js
new function getlink()
Authentication refactoring using ./route/secret.js
new route: getLink/:id, authentication refactoring using secret.js, socket-io for vote-updates
using express.io instead of express, cos deleted
Update Link with socketio