def save!
      result = Api.post("#{BASE_PATH}/#{customer_id}", body: attributes.to_json)
      Customer.new(result.parsed_response["rg_customer"])
    end
def save!
      result = Api.post("#{BASE_PATH}/#{customer_id}", body: attributes.to_json)
      Customer.new(result.parsed_response["rg_customer"])
    end
Create or update a customer with given id
 @return [Customer] if successfully created or updated
 @raise [Httparty::Error] for all sorts of HTTP statuses.