welcome activity, eventtypes: Forum=>Memo, Memo=>Reply.

app/models/memo.rb

@@ -20,7 +20,7 @@ class Memo < ActiveRecord::Base
 				  :datetime => :created_at,
 				  :description => :content,
 				  :author => :author,
-				  :type => Proc.new {|o| o.parent_id.nil? ? 'Forum' : 'Memo'},
+				  :type => Proc.new {|o| o.parent_id.nil? ? 'Memo' : 'Reply'},
 				  :url => Proc.new {|o| {:controller => 'memos', :action => 'show', :forum_id => o.forum_id}.merge(o.parent_id.nil? ? {:id => o.id} : {:id => o.parent_id, :anchor => "reply-#{o.id}"})}
 	acts_as_activity_provider :author_key => :author_id,
 							  :func => 'memos',