fix post_tag and if bulletin's rss2_sn is the same not insert

app/helpers/admin/announcements_helper.rb

@@ -216,8 +216,12 @@ module Admin::AnnouncementsHelper
 
     doc.xpath("//channel").each do|channel_data|
       channel_data.xpath('//item').each  do|itme|
+
+        bu = Bulletin.where(:rss2_sn =>  itme.xpath('wp:post_id').text ).first rescue nil
+        if bu.nil?
             bu = Bulletin.new
             bu.approved = true
+            bu.rss2_sn            = itme.xpath('wp:post_id').text
             bu.title_translations = {"en" => itme.xpath('title').text, "zh_tw" => itme.xpath('title').text}
             bu.text_translations  = {"en" => itme.xpath('content:encoded').text, "zh_tw" => itme.xpath('content:encoded').text}
             bu.postdate           = itme.xpath('wp:post_date').text
@@ -232,24 +236,26 @@ module Admin::AnnouncementsHelper
                     cat.title_translations = {"en" => i_cate.text.to_s, "zh_tw" => i_cate.text.to_s}
                     cat.save
                   end
-
                   bu.category = cat
 
               elsif i_cate["domain"].to_s == "post_tag"
 
-            tag = Tag.where(:name =>  i_cate.text.to_s )             
+                  tag = Tag.where(:name =>  i_cate.text.to_s ).first rescue nil
-            if tag.nil? == false
+                  if tag.nil?
                     tag = Tag.new
                     tag.name_translations = {"en" => i_cate.text.to_s, "zh_tw" => i_cate.text.to_s}
                     tag.module_app_ids << @module_app.id
                     tag.save
                   end
 
-            bu.tags=tag
+                  bu.tags = tag
               end
             end
+
         bu.save
         end
+
+      end
     end
     File.delete(xmlfile)
   end