The data is saved under the base child not in the location specified in the database in Firebase

Referring the example for the NoteApp

When fab is clicked and the note is saved, then in the database in Firebase console and the data is added under the main child rather then at /notes/user-id/.

Help me with this issue.

<link rel="import" href="bower_components/note-app-elements/na-elements.html">
<link rel="import" href="bower_components/app-storage/app-indexeddb-mirror/app-indexeddb-mirror.html">
<link rel="import" href="bower_components/polymerfire/polymerfire.html">

<dom-module id="note-app">
  <template>
    <style include="note-app-shared-styles"></style>

    <na-toolbar
        signed-in="[[signedIn]]"
        on-sign-out="signOut">
        </na-toolbar>

    <na-login
            on-sign-in="signIn"
            signed-in="[[signedIn]]"
            disabled="[[!online]]">
    </na-login>

    <firebase-auth
            id="auth"
            app-name="linkshare"
            provider="google"
            signed-in=""
        user="">
        </firebase-auth>

        <paper-fab
            icon="add"
            on-tap="create"
            disabled="[[!online]]"
            aria-label="Add note">
        </paper-fab>

        <na-editor
            id="editor"
            note=""
            on-close="commitChange">
        </na-editor>

        <firebase-document
            id="document"
            app-name="linkshare"
            path="[[editableNoteId]]"
            data="">
        </firebase-document>

<firebase-query
            id="query"
            app-name="linkshare"
            path="/notes/[[user.uid]]"
            data="">
        </firebase-query>

        <app-indexeddb-mirror
            session="[[user.uid]]"
            key="notes"
            data=""
            persisted-data="">
        </app-indexeddb-mirror>

        <div class="notes">
          <template is="dom-repeat" items="[[persistedNotes]]" as="note">
            <na-note
                id$="[[note.$key]]"
                title="[[note.title]]"
                body="[[note.body]]"
                on-tap="edit">
            </na-note>
          </template>
        </div>
        
  </template>
    
  <script>
        Polymer({
                is: 'note-app',

                behaviors: [Polymer.NoteAppBehavior],

                signIn: function() {
                this.$.auth.signInWithPopup();
                        },

                save: function() {              
                        this.$.document.saveValue();
                        },

                get notesPath() {
                        return '/notes/' + this.user.uid;
            },

            toEditableId: function(noteId) {
                        return this.notesPath + '/' + noteId;
            },

            get isEditable() {
                        return this.online;
            }
        });
  </script>
</dom-module>