Use startServer function

server.js

@@ -4,11 +4,7 @@ const createApp = require('./server/createApp')
 
 const port = parseInt(process.env.PORT, 10) || 5000
 
-throng({
-  workers: process.env.WEB_CONCURRENCY || 1,
-  lifetime: Infinity,
-  grace: 25000,
-  start: function (id) {
+function startServer(id) {
   const server = http.createServer(createApp())
 
   // Heroku dynos automatically timeout after 30s. Set our
@@ -18,18 +14,24 @@ throng({
     const message = `Timeout of 25 seconds exceeded`
 
     socket.end([
-        `HTTP/1.1 503 Service Unavailable`,
-        `Date: ${(new Date).toGMTString()}`,
-        `Content-Type: text/plain`,
-        `Content-Length: ${Buffer.byteLength(message)}`,
-        `Connection: close`,
-        ``,
+      'HTTP/1.1 503 Service Unavailable',
+      'Date: ' + (new Date).toGMTString(),
+      'Content-Length: ' + Buffer.byteLength(message),
+      'Content-Type: text/plain',
+      'Connection: close',
+      '',
       message
-      ].join(`\r\n`))
+    ].join('\r\n'))
   })
 
   server.listen(port, function () {
     console.log('Server #%s listening on port %s, Ctrl+C to stop', id, port)
   })
-  }
+}
+
+throng({
+  workers: process.env.WEB_CONCURRENCY || 1,
+  lifetime: Infinity,
+  grace: 25000,
+  start: startServer
 })