新增：字符串截取展示

app/views/admins/feedbacks/_list.html.erb

@@ -17,7 +17,11 @@
         <td><%= feedback&.user&.login%></td>
         <td><%= feedback&.user&.mail%></td>
         <td><%= feedback.created_at&.strftime('%Y-%m-%d %H:%M') %></td>
-        <td><%= feedback.content %></td>
+        <td>
+          <a href="#" data-toggle="tooltip" data-placement="bottom" title="<%= feedback.content%>">
+            <%= feedback.content.truncate(30) %>
+          </a>
+        </td>
         <td class="action-container">
           <%= link_to "发送邮件", new_history_admins_feedback_path(feedback), remote: true, class: "action" %>
           <%#= link_to "删除", admins_feedback_path(feedback), method: :delete, data:{confirm: "确认删除的吗？"}, class: "action" %>