diff --git a/app/controllers/admins/courses_controller.rb b/app/controllers/admins/courses_controller.rb
new file mode 100644
index 000000000..e69de29bb
diff --git a/app/controllers/attachments_controller.rb b/app/controllers/attachments_controller.rb
index da6e99418..0c9c49621 100644
--- a/app/controllers/attachments_controller.rb
+++ b/app/controllers/attachments_controller.rb
@@ -125,7 +125,7 @@ class AttachmentsController < ApplicationController
     end
 
     digest = md5_file(temp_file)
-    digest = "#{digest}_#{Time.now.to_i}"
+    digest = "#{digest}_#{(Time.now.to_f * 1000).to_i}"
     local_file_path = File.join(save_path, digest) + ext
     save_temp_file(temp_file, local_file_path)