replaced hardcode last-modified header with dynamically generated one

Author: jakewmeyer

app.js

@@ -24,6 +24,7 @@ app.use(cors())
 // Global HTTP headers
 app.use((req, res, next) => {
   res.header("Content-Type","application/json")
+  res.header("Last-Modified",new Date().toUTCString())
   next()
 })