code: function defaultConfiguration(config) {
    config = _.defaults({}, config, {
      name: 'Sparky',
      endpoint: '/relay',
      convos: [],
      sending_address: config.address,
      inbound_address: config.address,
      transport: 'sparkpost',
      restrict_inbound: true,
      logger: 'verbose',
      size_limit: '50mb'
    });
  
    config.address = cleanAddress(config.address);
    config.sending_address = cleanAddress(config.sending_address);
    config.inbound_address = cleanAddress(config.inbound_address);
  
    config.logger = _.isString(config.logger) ? require('./logger')(config.logger) : config.logger;
  
    return config;
  }
docs: generate the config
  
  @param {Object} config - the given config
  @returns {Configuration} config