Change call to check_output

app/flaskr.py

@@ -60,7 +60,7 @@ def deploy():
     if len(signature) < 2 or not hmac.compare_digest(signature, digest):
         abort(400, 'Invalid signature')
 
-    subprocess.call(['git', 'pull'])
-    subprocess.call(['pipenv', 'sync'])
-    subprocess.call(['touch', 'flask.wsgi'])
+    subprocess.check_output(['git', 'pull'])
+    subprocess.check_output(['pipenv', 'sync'])
+    subprocess.check_output(['touch', 'flask.wsgi'])
     return jsonify(True)