properly access book data

rusty-library/templates/book_card.html

@@ -1,7 +1,7 @@
  <article class="book-card">
   <header class="grid-item">
     <hgroup>
-      <h5>{{ book.title }}</h5>
+      <h5>{{ book.data.title }}</h5>
       <p>
          <a class="secondary" href="/authors/{{ book.author.id }}">{{ book.author.name }}</a>
       </p>
@@ -14,7 +14,7 @@
       {% endif %}
     </hgroup>
   </header>
-  <img class="cover" src="/cover/{{ book.id }}" alt="book cover">
+  <img class="cover" src="/cover/{{ book.data.id }}" alt="book cover">
   <footer>
     <form>
       <fieldset role="group">
@@ -24,7 +24,7 @@
           </summary>
           <ul>
           {% for format, _ in book.formats %}
-            <li><a href="/book/{{ book.id }}/{{ format }}">{{ format }}</a></li>
+            <li><a href="/book/{{ book.data.id }}/{{ format }}">{{ format }}</a></li>
           {% endfor %}
           </ul>
         </details>