feat(config): add ability to change elasticsearch logger

lib/elasticsearch_reader/config.rb

@@ -32,7 +32,7 @@ def initialize
     #
     def configuration
       yaml_settings.merge(settings.deep_symbolize_keys).tap do |configuration|
-        configuration[:logger]         = logger
+        configuration[:logger]         = logger if logger
         configuration[:indices_path] ||= indices_path
       end
     end

spec/elasticsearch_reader/config_spec.rb

@@ -1,13 +1,23 @@
 # frozen_string_literal: true
 
 require 'spec_helper'
+require 'logger'
 
 describe ElasticsearchReader::Config do
   subject { described_class.send(:new) }
 
   its(:logger) { should be_nil }
   its(:indices_path) { should == 'app/indices' }
 
+  describe '#transport_logger=' do
+    let(:logger) { Logger.new('/dev/null') }
+
+    specify do
+      expect { subject.logger = logger }
+        .to change { subject.logger }.to(logger)
+    end
+  end
+
   describe '#configuration' do
     before { subject.settings = { indices_path: 'app/foobar' } }