Check if current env is production and, if true, set port to 80 (#39)

src/server.js

@@ -1,7 +1,7 @@
 const express = require('express')
 const app = express()
 const path = require('path')
-const port = process.env.PORT || 3000
+const port = process.env.NODE_ENV === 'production' ? 80 : 3000
 require('./database/mongoose')
 const userRouter = require('./routes/user')
 const tokenRouter = require('./routes/token')