完成资源更新的时候 描述继承问题，并且可以修改描述

app/controllers/attachments_controller.rb

@@ -265,6 +265,10 @@ class AttachmentsController < ApplicationController
       @history.save  #历史记录保存完毕
       #将最新保存的记录 数据替换到 需要修改的文件记录
       @old_attachment.attributes = @attachment.attributes.dup.except("id","container_id","container_type","is_public","downloads", "quotes")
+      # 如果附件描述被修改，则保存附件
+      unless params[:description] == @attachment.description
+        @old_attachment.description = params[:description]
+      end
       @old_attachment.save
       #删除当前记录
       @attachment.delete

app/views/attachments/_show_attachment_history.html.erb

@@ -39,6 +39,14 @@
         <!--<a href="javascript:void(0);" class=" fr grey_btn mr40" onclick="closeModal();"><%#= l(:button_cancel)%></a>-->
         <!--<a id="submit_resource" href="javascript:void(0);" class="blue_btn fr" onclick="submit_resource();"><%#= l(:button_confirm)%></a>-->
       </div>
+      <div class="mb5">
+        <label class="fl c_dark f14" style="margin-top: 4px;">描述：</label>
+        <div class="fl">
+          <input  type="text" name="description" class="InputBox fl W160" value="<%= @attachment.description %>">
+        </div>
+        <div class="cl"></div>
+      </div>
+      <div class="cl"></div>
       <div class="uploadResourceIntr">
         <div class="uploadResourceName fl"><span id="upload_file_count">(未选择文件)</span></div>
         <div class="uploadResourceIntr2 fl">您可以上传小于<span class="c_red">50MB</span>的文件</div>