added edit button to author_detail.html

bookshelf/templates/bookshelf/author_detail.html

@@ -16,4 +16,9 @@
     <a href="/books/">Books</a>
     &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
     <a href="/authors/">Authors</a>
+    <br>
+    <br>
+    <a href="/authors/{{ authors.pk }}/edit/">
+        <input type="button" value="Edit Author">
+    </a>
 {% endblock %}
\ No newline at end of file