add testing environment

app/models/account_linked_account.rb

@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+# == Schema Information
+#
+# Table name: account_linked_accounts
+#
+#  id                :bigint           not null, primary key
+#  account_type      :text             not null
+#  created_at        :datetime         not null
+#  updated_at        :datetime         not null
+#  account_id        :bigint           not null
+#  linked_account_id :bigint           not null
+#
+# Indexes
+#
+#  idx_on_account_id_linked_account_id_48ab9f79d2      (account_id,linked_account_id) UNIQUE
+#  index_account_linked_accounts_on_account_id         (account_id)
+#  index_account_linked_accounts_on_linked_account_id  (linked_account_id)
+#
+# Foreign Keys
+#
+#  fk_rails_...  (account_id => accounts.id)
+#  fk_rails_...  (linked_account_id => accounts.id)
+#
+class AccountLinkedAccount < ApplicationRecord
+  belongs_to :account
+  belongs_to :linked_account, class_name: 'Account'
+
+  attribute :account_type, :string, default: 'testing'
+
+  scope :testing, -> { where(account_type: :testing) }
+
+  def testing?
+    account_type == 'testing'
+  end
+end