Update hello.py

Author: amgsnt

src/chat/hello.py

@@ -5,3 +5,7 @@
 @app.route("/")
 def hello():
     return "Hello World!"
+
+if __name__ == "__main__":
+    port = int(os.environ.get("PORT", 5000))
+    app.run(host='0.0.0.0', port=port)