Trouble saving current user

I have an application where users can log in and create records. I am
trying to get Rails to save the id/name of the user who created the
record. Somehow, the user id isn't getting stored, and I can't tell
why.

I'm rather new to Rails, and I'm cobbling together different tips from
different tutorials (and advice from friendly people here), and my guess
is that I've just mushed too much stuff together and don't know how to
integrate it all gracefully. Or, just as likely, there's some glaring
typo in my code.

In any case, here is the relevant part of the controller:

---------------------words_controller.rb-------------------
class WordsController < ApplicationController
   before_filter :login_required, :only => [ :new, :create, :edit,
:update, :delete ]
....
   def new
      @word = Word.new
   end
   def create
      @modword = (Modword.find_by_modspell(params[:modword][:modspell])

Modword.create(params[:modword]))

      @word = @current_user.words.build(params[:word])
      @word = Word.new(params[:word].merge(:modword_id => @modword.id))
        if @word.save
          redirect_to(:action => :index)
        else
          render :action => 'new'
      end
   end
....
end

You could also do: