Get admin area working again

js/admin/src/components/HeaderSecondary.js

@@ -0,0 +1,30 @@
+import Component from 'flarum/Component';
+import SessionDropdown from 'flarum/components/SessionDropdown';
+import ItemList from 'flarum/utils/ItemList';
+import listItems from 'flarum/helpers/listItems';
+
+/**
+ * The `HeaderSecondary` component displays secondary header controls.
+ */
+export default class HeaderSecondary extends Component {
+  view() {
+    return (
+      <ul className="Header-controls">
+        {listItems(this.items().toArray())}
+      </ul>
+    );
+  }
+
+  /**
+   * Build an item list for the controls.
+   *
+   * @return {ItemList}
+   */
+  items() {
+    const items = new ItemList();
+
+    items.add('session', SessionDropdown.component());
+
+    return items;
+  }
+}