module AdminHelper
 #add before_filter :authorize to any controller if you want to make sure a authorized user can view that page
 def current_user
    @current_user ||= User.find(session[:user_id]) if session[:user_id]
  end

  def authorize
    redirect_to '/login' unless current_user
  end
end

module AdminHelper
 #add before_filter :authorize to any controller if you want to make sure a authorized user can view that page
 def current_user
    @current_user ||= User.find(session[:user_id]) if session[:user_id]
  end

  def authorize
    redirect_to '/login' unless current_user
  end

  # check if user is admin
  def admin?
    User.find(session[:user_id]).admin
  end
end

Add check if user is admin
Add check if user is admin
