Clicking on an index nav item should always refresh the discussion list

js/forum/src/components/index-nav-item.js

@@ -0,0 +1,10 @@
+import NavItem from 'flarum/components/nav-item'
+
+export default class IndexNavItem extends NavItem {
+  static props(props) {
+    props.onclick = props.onclick || function() {
+      app.cache.discussionList = null;
+      m.redraw.strategy('none');
+    };
+  }
+}