作品评论时间显示为更新时间，并按更新时间排序

app/views/student_work/_show.html.erb

@@ -61,7 +61,7 @@
 </ul>
 
 <div class="ping_box mt10" id="score_list_<%= @work.id%>" style="<%= @work.student_works_scores.empty? ? 'padding:0px;' : ''%>">
-  <%@work.student_works_scores.order("created_at desc").each do |score|%>
+  <%@work.student_works_scores.order("updated_at desc").each do |score|%>
       <div id="work_score_<%= score.id%>">
         <%= render :partial => 'student_work_score',:locals => {:score => score}%>
       </div>

app/views/student_work/_student_work_score.html.erb

@@ -8,7 +8,7 @@
     <a href="javascript:void(0);" class="c_orange fl" ><%= score.score%>分</a>
     <a href="javascript:void(0);" class="fr c_purple mr5" onclick="$('#add_score_reply_<%= score.id%>').slideToggle();">回复</a>
           <span class=" fr c_grey mr20">
-            <%=format_time score.created_at %>
+            <%=format_time score.updated_at %>
           </span>
     <div class="cl mb5"></div>
     <p class="break_word">