pundit: convert pools to pundit.

app/controllers/pool_elements_controller.rb

@@ -1,15 +1,13 @@
 class PoolElementsController < ApplicationController
   respond_to :html, :xml, :json, :js
-  before_action :member_only
 
   def create
     @pool = Pool.find_by_name(params[:pool_name]) || Pool.find_by_id(params[:pool_id])
+    raise ActiveRecord::RecordNotFound if @pool.nil?
+    authorize(@pool, :update?)
 
-    if @pool.present? && !@pool.is_deleted?
-      @post = Post.find(params[:post_id])
-      @pool.add!(@post)
-    else
-      @error = "That pool does not exist"
-    end
+    @post = Post.find(params[:post_id])
+    @pool.add!(@post)
+    respond_with(@pool)
   end
 end