Update _index.md

app/_index.md

 ---
-title: APP
-draft: true
+title: Companion App
 ---
-# APP INSTALLATION INSTRUCTIONS GO HERE
+
+
+<div class="p-notification--caution">
+    <p class="p-notification__response">
+        <span class="p-notification__status">Warning:</span>
+        We are still in developing the Companion App for iOS and Android
+    </p>
+</div>
\ No newline at end of file