add DepositOrder model and query

spec/models/deposit_order_spec.rb

@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+# == Schema Information
+#
+# Table name: deposit_orders
+#
+#  id                    :bigint           not null, primary key
+#  paid_amount_cents     :integer          default(0), not null
+#  received_amount_cents :integer          default(0), not null
+#  status                :string           not null
+#  created_at            :datetime         not null
+#  updated_at            :datetime         not null
+#  user_id               :bigint           not null
+#
+# Indexes
+#
+#  index_deposit_orders_on_user_id  (user_id)
+#
+# Foreign Keys
+#
+#  fk_rails_...  (user_id => users.id)
+#
+require "rails_helper"
+
+RSpec.describe(DepositOrder, type: :model) do
+  pending "add some examples to (or delete) #{__FILE__}"
+end