def validate_token!(access_token)
      validator = Fridge.configuration.validator
      if validator.call(access_token)
        access_token
      else
        raise InvalidToken, 'Rejected by validator'
      end
    end
def validate_token!(access_token)
      validator = Fridge.configuration.validator
      if validator.call(access_token)
        access_token
      else
        raise InvalidToken, 'Rejected by validator'
      end
    end
Validates token, and raises an exception if invalid