serve css + js locally

public/index.html

@@ -21,7 +21,7 @@
     -->
     <link
       rel="stylesheet"
-      href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css"
+      href="css/bootstrap.min.css"
       integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T"
       crossorigin="anonymous"
     />
@@ -41,17 +41,17 @@
       To create a production bundle, use `npm run build` or `yarn build`.
     -->
     <script
-      src="https://code.jquery.com/jquery-3.3.1.slim.min.js"
+      src="js/jquery-3.3.1.slim.min.js"
       integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo"
       crossorigin="anonymous"
     ></script>
     <script
-      src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js"
+      src="js/popper.min.js"
       integrity="sha384-UO2eT0CpHqdSJQ6hJty5KVphtPhzWj9WO1clHTMGa3JDZwrnQq4sF86dIHNDz0W1"
       crossorigin="anonymous"
     ></script>
     <script
-      src="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js"
+      src="js/bootstrap.min.js"
       integrity="sha384-JjSmVgyd0p3pXB1rRibZUAYoIIy6OrQ6VrjIEaFf/nJGzIxFDsf4x0xIM+B07jRM"
       crossorigin="anonymous"
     ></script>