Attaching user to comment

How would I attach as user to the form input being added into the db? User name is defined as @current_user in application.rb

def comment

@albums = Albums.find(params[:id]) @albumscomment = Albums.find(params[:id]).comments.create(params[:comment])

    if request.post? and @albumscomment.save     flash[:notice] = 'comment submission succeeded!'     redirect_to :action => 'show', :permalink => @albums.permalink     end

end

def comment @albums = Albums.find(params[:id]) @albumscomment = Albums.find(params[:id]).comments.create(params[:comment]) @albumscomment.username = @current_user    if request.post? and @albumscomment.save          flash[:notice] = 'comment submission succeeded!'          redirect_to :action => 'show', :permalink => @albums.permalink    end end