Edit singup's uploaded filename display.

Edit email contents of file upload or edit.

app/models/seminar_signup_contribute.rb

@@ -8,6 +8,7 @@ class SeminarSignupContribute
   field :presentation_type , type: String , default: ""
   field :sort_number , type: Integer, default: 10000
   mount_uploader :file, AssetUploader
+  field :filename, type: String
   field :description
   field :preferred_session
   field :final_session
@@ -40,4 +41,25 @@ class SeminarSignupContribute
 	    end
     end
   end
+  before_save do
+    self.update_filename
+  end
+  def update_filename
+    if self.title.blank?
+      self.filename = self.file.file.filename rescue ''
+    else
+      if self.file.file
+        self.filename = self.title.sub(/#{::Regexp.escape(File.extname(self.title))}$/,'') + File.extname(self.file.file.filename)
+      else
+        self.filename = self.title
+      end
+    end
+    self.filename
+  end
+  def disp_filename
+    if self.filename.nil?
+      self.class.where(:id=>self.id).update_all(:filename=>self.update_filename)
+    end
+    self.filename
+  end
 end