Rails - Apr 2009 - 'get_user_list' function not working

i want to show fullname by using fuction call ''get_user_list'' 
, but
its not working..??

tis s user.rb


(
def full_name
                self.first_name + "  " + self.last_name
        end )


my post controller


( def get_user_list
   return User.find(:all, :order => ''last_name
ASC'').collect {|user|
[user.full_name, user.id]}


NameError in PostsController#edit
undefined local variable or method `get_user_list'' for
#<PostsController:0x47c8360>