Actually delete the work dir

server.py

@@ -5,6 +5,7 @@ import os
 from celery import Celery
 from datetime import datetime, timedelta
 from flask import Flask, abort, request, Response, send_file
+from shutil import rmtree
 import pypandoc
 
 app = Flask(__name__)
@@ -61,4 +62,4 @@ def convert():
 @celery.task()
 def clean_up(path):
     app.logger.info('Deleting work dir %s', path)
-    pass
+    rmtree(path)