Added user online indicator to post

js/forum/src/components/PostUser.js

@@ -45,6 +45,7 @@ export default class PostUser extends Component {
 
     return (
       <div className="PostUser">
+        {useronline(user)}
         <h3>
           <a href={app.route.user(user)} config={m.route}>
             {avatar(user, {className: 'PostUser-avatar'})}{' '}{username(user)}

js/lib/helpers/useronline.js

@@ -0,0 +1,13 @@
+import icon from 'flarum/helpers/icon';
+
+/**
+ * The `useronline` helper displays a green circle if the user is online
+ *
+ * @param {User} user
+ * @return {Object}
+ */
+export default function useronline(user) {
+    if (user.lastSeenTime() && user.isOnline()) {
+        return <span className="UserOnline">{icon('circle')}</span>;
+    }
+}