问Rails 3:获取当前user_id以保存在不同的模型中

EN

class Article < ActiveRecord::Base
  belongs_to :user
  attr_accessible :title, :description, :user_id

  validates_length_of :title, :minimum => 5
end

def create
    @article = Article.new(params[:article])

    respond_to do |format|
      if @article.save
        format.html { redirect_to @article, notice: 'Article was successfully created.' }
        format.json { render json: @article, status: :created, location: @article }
      else
        format.html { render action: "new" }
        format.json { render json: @article.errors, status: :unprocessable_entity }
      end
    end
  end

<div class="field">
    <%= f.label :title %><br />
    <%= f.text_field :title %>
  </div>
  <div class="field">
    <%= f.label :description %><br />
    <%= f.text_area :description %>
  </div>

class ApplicationController < ActionController::Base
  protect_from_forgery

  helper_method :current_user

  private
  def current_user
    @current_user ||= User.find(session[:user_id]) if session[:user_id]
  end
end