application_controller.rb

class ApplicationController < ActionController::Base
  protect_from_forgery
  before_filter :current_user

  protected
  def current_user
    @current_user ||= User.where(:id => session[:user_id]).first
  end

  def require_authenticate
    unless current_user
      redirect_to root_url
      return false
    end
  end

  helper_method :current_user
end