fix(home.html.erb): fix the undefined method exception for sorting viewers on the home page (ifmeorg#895)

Author: nma

app/views/pages/home.html.erb

@@ -7,7 +7,7 @@
   <div id="pages">
     <div class="page">
       <% @stories.each do |story| %>
-        <% if current_user.id == story.userid || (is_viewer(story.viewers) && are_allies?(current_user.id, story.userid)) %>
+        <% if current_user.id == story.userid || (viewer_of?(story.viewers) && are_allies?(current_user.id, story.userid)) %>
           <div class="story">
             <div class="align_left">
               <h1 class="story_name">