spawn defined under shepherd api

routes/shepherd.js

@@ -10,6 +10,7 @@ const electron = require('electron'),
       mkdirp = require('mkdirp'),
       express = require('express'),
       exec = require('child_process').exec,
+      spawn = require('child_process').spawn,
       md5 = require('md5'),
       pm2 = require('pm2'),
       request = require('request'),