added import sys to tornado server

Author: smcgregor

tornado_server.py

@@ -2,6 +2,7 @@
 from tornado.httpserver import HTTPServer
 from tornado.ioloop import IOLoop
 from flask_server import app
+import sys
 
 http_server = HTTPServer(WSGIContainer(app))
 # There is an optional parameter for selecting between multiple domains in the