_nav

  <% if @post.prev.present? %>
    <%= link_to(("&#171; " + truncate(@post.prev.title)).html_safe, 
                refinery.blog_post_path(@post.prev), 
                :class => 'prev button') do %>
			 <h1>Previous</h1>
	  <% end -%>
  <% end -%>



error:

undefined method `stringify_keys' for "/blog/posts/ovo-je-naslov-drugog-blog-posta":String


html I am expecting to get out of it:

<a class="prev button" href="/blog/ovo-je-naslov-drugog-blog-posta">  			      
  <h1>Previous</h1>
  <h2>PAIRING OF THE WEEK: Pata C...</h2>
</a>

<%= link_to(refinery.blog_post_path(@post.prev)) do %>
<h1>Previous</h1>
<h2><%= "&#171; " + truncate(@post.prev.title)).html_safe %></h2>
<% end %>