fix mail cron send mail del log

app/mailer/mail_cron_mailer.rb

@@ -63,7 +63,6 @@ class MailCronMailer < ActionMailer::Base
         end 
       end 
 
-
       @mail_cron_log = {  
         :mail_subject => @data.mail_subject,
         :mail_to => group_mail,
@@ -74,10 +73,16 @@ class MailCronMailer < ActionMailer::Base
 
       @mail_cron_log = MailCronLog.new(@mail_cron_log) 
 
-
       @mail_cron_log.save
 
-      @data.destroy
+      @mail_to_count = @data.mail_to.split(',') - group_mail.split(',')
+
+      if @mail_to_count.count == 0
+        @data.destroy
+      else
+        @data.mail_to = @mail_to_count.join(',')
+        @data.save
+      end
 
     end