add series and author links to books

rusty-library/templates/book_card.html

@@ -2,7 +2,16 @@
   <header class="grid-item">
     <hgroup>
       <h5>{{ book.title }}</h5>
-      <p>{{ book.author }}</p>
+      <p>
+         <a class="secondary" href="/authors/{{ book.author.id }}">{{ book.author.name }}</a>
+      </p>
+      {% if book.series %}
+      <p>
+        <small>
+          <a class="secondary" href="/series/{{ book.series.0.id }}">{{ book.series.0.name }} ({{ book.series.1 }})</a>
+        </small>
+      </p>
+      {% endif %}
     </hgroup>
   </header>
   <img class="cover" src="/cover/{{ book.id }}" alt="book cover">