operation.rb

    def create_documents
      order = self.order
      customer_doc = order.documents.create!
      contractor_doc = self.documents.create!
      customer_doc.tranzactions.create! account_id: order.user.accounts.transit.id, amount: (order.price * -1)
      contractor_doc.tranzactions.create! account_id: self.user.accounts.transit.id, amount: (order.price * +1)
    end