add ui

ui/pages/problem_submit.page.js

@@ -0,0 +1,10 @@
+import { NamedPage } from 'vj/misc/PageLoader';
+
+const page = new NamedPage('problem_submit', async () => {
+  $(document).on('click', '[name="problem-sidebar__show-category"]', (ev) => {
+    $(ev.currentTarget).hide();
+    $('[name="problem-sidebar__categories"]').show();
+  });
+});
+
+export default page;