use local source

public/index.html

@@ -67,7 +67,7 @@
     <!-- Bootstrap core JavaScript
     ================================================== -->
     <!-- Placed at the end of the document so the pages load faster -->
-    <script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script>
+    <script src="assets/jquery-3.2.1.slim.min.js"></script>
     <script>window.jQuery || document.write('<script src="assets/jquery-slim.min.js"><\/script>')</script>
     <script src="assets/popper.min.js"></script>
     <script src="assets/bootstrap.min.js"></script>