Add link to books page

templates/base.html

@@ -12,6 +12,7 @@
 	<a href="{{ get_url(path='/') }}">Home</a>
 	<a href="{{ get_url(path='@/about.md') }}">About</a>
 	<a href="{{ get_url(path='@/blog/_index.md') }}">Posts</a>
+	<a href="{{ get_url(path='@/books.md') }}">Books</a>
     </nav>
   </header>
   <section class="section">