Including plugin module giving an error

Hi,
I am developing a plugin for database search in rails 3. I have created
a plugin with name “db_search”.
I have written following code in
“/vendor/plugins/db_search/lib/db_search.rb”
“require File.join(File.dirname(FILE), ‘db_search/core’)”

Then I have written following code in
“vendor/plugins/db_search/lib/db_search/core.rb”
“module TRG
module DBSEARCH
def with()
p “I am in with”
end
end
end”

To make my search independent of models I have created search.rb in the
“/model”. I have added following code:-

“class Search
include TRG::DBSEARCH
end”

I have user controller. I have written a following method into it:-
def search
Search.new
end
Whenever I am running this method I am getting an error:-
“uninitialized constant Search::TRG”

I also Tried with “TRG::DBSEARCH.with()” but no luck

I don’t know why my plugin modules are not get loaded.
Can anyone tell me what is wrong with the code?