add cashier zones

app/models/cashier_terminal_by_zone.rb

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+class CashierTerminalByZone < ApplicationRecord
+end

db/migrate/20171023032411_create_cashier_terminal_by_zones.rb

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+class CreateCashierTerminalByZones < ActiveRecord::Migration[5.1]
+  def change
+    create_table :cashier_terminal_by_zones do |t|
+      t.integer :cashier_terminal_id
+      t.integer :zone_id
+
+      t.timestamps
+    end
+  end
+end

spec/models/cashier_terminal_by_zone_spec.rb

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+require 'rails_helper'
+
+RSpec.describe CashierTerminalByZone, type: :model do
+  pending "add some examples to (or delete) #{__FILE__}"
+end