Add navigators for previous post and next post in every post

_layouts/post.html

@@ -13,6 +13,13 @@ <h1>{{ page.title }}</h1>
         {{content}}
       </article>
       <hr>
+      {% if page.previous %}
+      <a href="{{page.previous.url | prepend:site.baseurl | replace:'//','/'}}">上一篇博客：{{page.previous.title}}</a><br>
+      {% endif %}
+      {% if page.next %}
+      <a href="{{page.next.url | prepend:site.baseurl | replace:'//','/'}}">下一篇博客：{{page.next.title}}</a>
+      {% endif %}
+      <hr>
       <div class="bdsharebuttonbox"><a href="#" class="bds_more" data-cmd="more"></a><a href="#" class="bds_tsina" data-cmd="tsina" title="分享到新浪微博"></a><a href="#" class="bds_weixin" data-cmd="weixin" title="分享到微信"></a><a href="#" class="bds_douban" data-cmd="douban" title="分享到豆瓣网"></a><a href="#" class="bds_fbook" data-cmd="fbook" title="分享到Facebook"></a><a href="#" class="bds_copy" data-cmd="copy" title="分享到复制网址"></a></div>
       <script>window._bd_share_config={"common":{"bdSnsKey":{},"bdText":"","bdMini":"2","bdMiniList":false,"bdPic":"","bdStyle":"1","bdSize":"24"},"share":{}};with(document)0[(getElementsByTagName('head')[0]||body).appendChild(createElement('script')).src='http://bdimg.share.baidu.com/static/api/js/share.js?v=89860593.js?cdnversion='+~(-new Date()/36e5)];</script>
     </div>
@@ -34,4 +41,4 @@ <h1>{{ page.title }}</h1>
       <div class="content-text"></div>
     </div>
   </div>
-</div>
+</div>