diff --git a/Gemfile b/Gemfile
index a6e0bdd54..54d1f540c 100644
--- a/Gemfile
+++ b/Gemfile
@@ -24,6 +24,7 @@ gem 'puma', '~> 3.7'
 
 # Use Rack CORS for handling Cross-Origin Resource Sharing (CORS), making cross-origin AJAX possible
 # gem 'rack-cors'
+gem "active_model_serializers"
 
 group :development, :test do
   # Call 'byebug' anywhere in the code to stop execution and get a debugger console
diff --git a/Gemfile.lock b/Gemfile.lock
index 4a738acb5..7cc8096f2 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -24,6 +24,11 @@ GEM
       erubi (~> 1.4)
       rails-dom-testing (~> 2.0)
       rails-html-sanitizer (~> 1.0, >= 1.0.3)
+    active_model_serializers (0.10.6)
+      actionpack (>= 4.1, < 6)
+      activemodel (>= 4.1, < 6)
+      case_transform (>= 0.2)
+      jsonapi-renderer (>= 0.1.1.beta1, < 0.2)
     activejob (5.1.4)
       activesupport (= 5.1.4)
       globalid (>= 0.3.6)
@@ -48,6 +53,8 @@ GEM
       debug_inspector (>= 0.0.1)
     builder (3.2.3)
     byebug (9.1.0)
+    case_transform (0.2)
+      activesupport
     coderay (1.1.2)
     concurrent-ruby (1.0.5)
     crass (1.0.2)
@@ -61,6 +68,7 @@ GEM
     jquery-turbolinks (2.1.0)
       railties (>= 3.1.0)
       turbolinks
+    jsonapi-renderer (0.1.3)
     listen (3.1.5)
       rb-fsevent (~> 0.9, >= 0.9.4)
       rb-inotify (~> 0.9, >= 0.9.7)
@@ -151,6 +159,7 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
+  active_model_serializers
   better_errors
   binding_of_caller
   byebug
diff --git a/app/controllers/customers_controller.rb b/app/controllers/customers_controller.rb
index 456569149..c3919a8f6 100644
--- a/app/controllers/customers_controller.rb
+++ b/app/controllers/customers_controller.rb
@@ -1,8 +1,9 @@
 class CustomersController < ApplicationController
 def index
   customers = Customer.all
+  # render json: customers, status: :ok
   render(
-    json: customers.as_json(only: [:id, :name, :registered_at, :address, :city, :state, :postal_code, :phone])
+    json: customers.as_json(only: [:id, :name, :registered_at, :address, :city, :state, :postal_code, :phone], methods: [ :movies_checked_out_count])
   )
 end
 end
diff --git a/app/controllers/movies_controller.rb b/app/controllers/movies_controller.rb
index 824101aa6..223fcdfbf 100644
--- a/app/controllers/movies_controller.rb
+++ b/app/controllers/movies_controller.rb
@@ -1,5 +1,4 @@
 class MoviesController < ApplicationController
-  # protect_from_forgery with: :null_session
 
   def index
     movies = Movie.all
diff --git a/app/models/customer.rb b/app/models/customer.rb
index d24ae68b0..8f4558692 100644
--- a/app/models/customer.rb
+++ b/app/models/customer.rb
@@ -1,7 +1,12 @@
 class Customer < ApplicationRecord
+  # include ActiveModel::Serialization
+
   has_many :rentals
 
   validates :name, presence: true
 
-  
+  def movies_checked_out_count
+    self.rentals.where(checked_out: true).count
+  end # movies_checked_out
+
 end
diff --git a/app/serializers/customer_serializer.rb b/app/serializers/customer_serializer.rb
new file mode 100644
index 000000000..336c84d80
--- /dev/null
+++ b/app/serializers/customer_serializer.rb
@@ -0,0 +1,3 @@
+# class CustomerSerializer < ActiveModel::Serializer
+#   attributes :id, :name, :registered_at, :address, :city, :state, :postal_code, :phone, :movies_checked_out_count
+# end
diff --git a/db/migrate/20171107181648_add_checked_out.rb b/db/migrate/20171107181648_add_checked_out.rb
new file mode 100644
index 000000000..902b8ef27
--- /dev/null
+++ b/db/migrate/20171107181648_add_checked_out.rb
@@ -0,0 +1,5 @@
+class AddCheckedOut < ActiveRecord::Migration[5.1]
+  def change
+    add_column :rentals, :checked_out, :boolean
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 73c02b67f..6f7142676 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20171106215231) do
+ActiveRecord::Schema.define(version: 20171107181648) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -43,6 +43,7 @@
     t.date "due_date"
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
+    t.boolean "checked_out"
   end
 
 end
diff --git a/test/fixtures/rentals.yml b/test/fixtures/rentals.yml
index b9677884e..fb50b9fe7 100644
--- a/test/fixtures/rentals.yml
+++ b/test/fixtures/rentals.yml
@@ -5,6 +5,7 @@ one:
   customer_id: 1
   due_date: 2017-11-06
 
+
 two:
   movie_id: 1
   customer_id: 1
diff --git a/test/models/customer_test.rb b/test/models/customer_test.rb
index e3ce77543..3f077bc1e 100644
--- a/test/models/customer_test.rb
+++ b/test/models/customer_test.rb
@@ -27,4 +27,15 @@
 
     end
   end # validations
+
+  # describe "custom methods" do
+  #   describe "movies_checked_out" do
+  #     it "will return a list of the checkout out movies for that customer" do
+  #       get customers_path
+  #
+  #       body = JSON.parse(response.body)
+  #       body[0][:movies_checked_out].must_equal 0
+  #     end
+  #   end # movies_checked_out
+  # end # custom methods
 end