Add orders_count and ordering on overview

app/controllers/orders_controller.rb

@@ -27,7 +27,7 @@ class OrdersController < ApplicationController
 
   def index
     @users_by_name = User.all.order(:name)
-    @users_by_order = User.all
+    @users_by_order = User.all.order(:orders_count).reverse_order
   end
 
   private

app/models/order.rb

@@ -11,7 +11,7 @@
 
 class Order < ActiveRecord::Base
   after_initialize { self.total_price = 0 }
-  belongs_to :user
+  belongs_to :user, counter_cache: true
 
   has_many :order_products
   has_many :products, { through: :order_products} do

db/migrate/20141210090544_add_orders_count_to_users.rb

@@ -0,0 +1,5 @@
+class AddOrdersCountToUsers < ActiveRecord::Migration
+  def change
+    add_column :users, :orders_count, :integer, default: 0
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20141209204351) do
+ActiveRecord::Schema.define(version: 20141210090544) do
 
   create_table "order_products", force: true do |t|
     t.integer "order_id"
@@ -60,6 +60,7 @@ ActiveRecord::Schema.define(version: 20141209204351) do
     t.string   "avatar_content_type"
     t.integer  "avatar_file_size"
     t.datetime "avatar_updated_at"
+    t.integer  "orders_count",        default: 0
   end
 
 end