try to fix joi problem

backend/routes/routesToucan.js

@@ -139,7 +139,7 @@ router.route("/img/:id")
     });
 
 router.route("/pdf/:url")
-    .get(celebrate({query: validURL}), function(req,res) {
+    .get(celebrate(), function(req,res) {
         urltoucans.findOne({urlID: req.params.url}, (err,data) => {
             if (err) {
                 res.end(500);