add BuyCryptoOrder and SellCryptoOrder entities

app/models/buy_crypto_order.rb

@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+# == Schema Information
+#
+# Table name: buy_crypto_orders
+#
+#  id                :bigint           not null, primary key
+#  paid_amount_cents :integer          default(0), not null
+#  received_amount   :decimal(20, 10)
+#  status            :string           not null
+#  created_at        :datetime         not null
+#  updated_at        :datetime         not null
+#  currency_id       :bigint           not null
+#  user_id           :bigint           not null
+#
+# Indexes
+#
+#  index_buy_crypto_orders_on_currency_id  (currency_id)
+#  index_buy_crypto_orders_on_user_id      (user_id)
+#
+# Foreign Keys
+#
+#  fk_rails_...  (currency_id => currencies.id)
+#  fk_rails_...  (user_id => users.id)
+#
+class BuyCryptoOrder < ApplicationRecord
+  include Processable
+
+  belongs_to :user
+  belongs_to :currency
+
+  monetize :paid_amount_cents
+
+  validates :paid_amount_cents, presence: true, numericality: { greater_than: 0 }
+  validates :received_amount, presence: true, if: :completed?
+end

app/models/concerns/processable.rb

@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+module Processable
+  extend Enumerize
+  extend ActiveSupport::Concern
+
+  included do
+    enumerize :status, in: [:processing, :completed, :canceled], default: :processing
+  end
+
+  def processing?
+    status == :processing
+  end
+
+  def completed?
+    status == :completed
+  end
+
+  def canceled?
+    status == :canceled
+  end
+end

app/models/sell_crypto_order.rb

@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+# == Schema Information
+#
+# Table name: sell_crypto_orders
+#
+#  id                    :bigint           not null, primary key
+#  paid_amount           :decimal(20, 10)  default(0.0), not null
+#  received_amount_cents :integer
+#  status                :string           not null
+#  created_at            :datetime         not null
+#  updated_at            :datetime         not null
+#  currency_id           :bigint           not null
+#  user_id               :bigint           not null
+#
+# Indexes
+#
+#  index_sell_crypto_orders_on_currency_id  (currency_id)
+#  index_sell_crypto_orders_on_user_id      (user_id)
+#
+# Foreign Keys
+#
+#  fk_rails_...  (currency_id => currencies.id)
+#  fk_rails_...  (user_id => users.id)
+#
+class SellCryptoOrder < ApplicationRecord
+  include Processable
+
+  belongs_to :user
+  belongs_to :currency
+
+  monetize :received_amount_cents
+
+  validates :paid_amount, presence: true, numericality: { greater_than: 0 }
+  validates :received_amount_cents, presence: true, if: :completed?
+end