```ruby
require 'doorkeeper/grape/helpers'

module API
  module V1
    class Customers < Grape::API
      helpers Doorkeeper::Grape::Helpers

      helpers do

        def current_customer
          @current_customer ||=
            Customer.find(doorkeeper_token.resource_owner_id)
        end
      end
      include API::V1::Defaults

      before do
        doorkeeper_authorize! :customer
      end

      # before_action -> { doorkeeper_authorize! :customer }, only: :index
      # before_action only: [:create, :update, :destroy] do
      #   doorkeeper_authorize! :admin
      # end

      resource :customers do

        get 'me' do
          current_customer
        end

        post 'me' do
          current_customer
        end

        desc "Get all customer's discount cards with barcodes"
        post 'full_info' do
          current_customer.as_json(include:
            { discount_cards: { include: :barcode } }).to_json
        end

        desc "Update current customer's info"
        put 'update' do
          current_customer.first_name ||= params[:first_name]
          current_customer.last_name ||= params[:last_name]
          current_customer.country ||= params[:country]
          current_customer.city ||= params[:city]
          current_customer.phone_number ||= params[:phone_number]
          current_customer.password ||= params[:password]
          current_customer.save!
        end
      end

      private

      def current_customer
        @current_customer ||= Customer.find(doorkeeper_token.resource_owner_id)
      end
    end
  end
end
```

Make /full_info api return discount cards with barcodes
user
```ruby
require 'doorkeeper/grape/helpers'

module API
  module V1
    class Customers < Grape::API
      helpers Doorkeeper::Grape::Helpers

      helpers do

        def current_customer
          @current_customer ||=
            Customer.find(doorkeeper_token.resource_owner_id)
        end
      end
      include API::V1::Defaults

      before do
        doorkeeper_authorize! :customer
      end

      # before_action -> { doorkeeper_authorize! :customer }, only: :index
      # before_action only: [:create, :update, :destroy] do
      #   doorkeeper_authorize! :admin
      # end

      resource :customers do

        get 'me' do
          current_customer
        end

        post 'me' do
          current_customer
        end

        desc "Get all customer's discount cards with barcodes"
        post 'full_info' do
          current_customer.to_json(include:
            { discount_cards: { include: :barcode } })
        end

        desc "Update current customer's info"
        put 'update' do
          current_customer.first_name ||= params[:first_name]
          current_customer.last_name ||= params[:last_name]
          current_customer.country ||= params[:country]
          current_customer.city ||= params[:city]
          current_customer.phone_number ||= params[:phone_number]
          current_customer.password ||= params[:password]
          current_customer.save!
        end
      end

      private

      def current_customer
        @current_customer ||= Customer.find(doorkeeper_token.resource_owner_id)
      end
    end
  end
end
```
assistant