def configuration
      yaml_settings.merge(settings.deep_symbolize_keys).tap do |configuration|
        configuration[:logger] = transport_logger if transport_logger
        configuration[:indices_path] ||= indices_path if indices_path
        configuration.merge!(tracer: transport_tracer) if transport_tracer
      end
    end
def configuration
      yaml_settings.merge(settings.deep_symbolize_keys).tap do |configuration|
        configuration[:logger] = transport_logger if transport_logger
        configuration[:indices_path] ||= indices_path if indices_path
        configuration.merge!(tracer: transport_tracer) if transport_tracer
      end
    end
Chewy core configurations. There is two ways to set it up:
 use `Chewy.settings=` method or, for Rails application,
 create `config/chewy.yml` file. Btw, `config/chewy.yml` supports
 ERB the same way as ActiveRecord's config.

 Configuration options:

   1. Chewy client options. All the options Elasticsearch::Client
      supports.

        test:
          host: 'localhost:9250'

   2. Chewy self-configuration:

      :prefix - used as prefix for any index created.

        test:
          host: 'localhost:9250'
          prefix: test<%= ENV['TEST_ENV_NUMBER'] %>

      Then UsersIndex.index_name will be "test42_users"
      in case TEST_ENV_NUMBER=42

      :wait_for_status - if this option set - chewy actions such
      as creating or deleting index, importing data will wait for
      the status specified. Extremely useful for tests under heavy
      indexes manipulations.

        test:
          host: 'localhost:9250'
          wait_for_status: green

   3. Index settings. All the possible ElasticSearch index settings.
      Will be merged as defaults with index settings on every index
      creation.

        test: &test
          host: 'localhost:9250'
          index:
            number_of_shards: 1
            number_of_replicas: 0