Added authorship rel attribute to post author link

loop-single.php

@@ -7,7 +7,7 @@
 				<h1 class="entry-title"><?php the_title(); ?></h1>
 				<time class="updated" datetime="<?php the_time('c'); ?>" pubdate><?php printf(__('Posted on %s at %s.', 'roots'), get_the_time('l, F jS, Y'),get_the_time())?></time>
 				<p class="byline author vcard">
-					<?php _e('Written by', 'roots');?> <span class="fn"><?php the_author(); ?></span>
+        <?php _e('Written by', 'roots');?> <?php the_author_posts_link(); ?>
 				</p>
 			</header>
 			<div class="entry-content">