example bank account class

bank_account.rb

module Banking
  module PaymentMethods
    class BankAccount < ActiveRecord::Base
      belongs_to :user
      has_many :transactions, class_name: 'Banking::Transaction'
      
      def debit(amount)
        Processing::Debit.execute(amount, self) 
        # Or Processing::Debit.new(amount, self).process! depending on your desired API
      end
      
      def credit(amount)
        Processing::Credit.execute(amount, self) 
        # Or Processing::Credit.new(amount, self).process!
      end
    end
  end
end