change _add_tags method to play nice with rails 2.2

generators/tagging/templates/tagging_extensions.rb

@@ -1,4 +1,3 @@
-
 class ActiveRecord::Base #:nodoc:
 
   # These extensions make models taggable. This file is automatically generated and required by your app if you run the tagging generator included with has_many_polymorphs.
@@ -13,7 +12,7 @@ def _add_tags incoming
         begin
           tag = Tag.find_or_create_by_name(tag_name)
           raise Tag::Error, "tag could not be saved: #{tag_name}" if tag.new_record?
-          tag.taggables << self
+          tags << tag
         rescue ActiveRecord::StatementInvalid => e
           raise unless e.to_s =~ /duplicate/i
         end
@@ -66,7 +65,11 @@ def tag_list #:nodoc:
       <%= parent_association_name -%>s.to_s
       #:startdoc:
     end
-    
+
+    def tag_list=(value)
+        tag_with(value)
+    end    
+
     private 
     
     def tag_cast_to_string obj #:nodoc: