final_config.rb

# config/elastic_search.rb
ElasticSearchSettingsForUser = YAML.load_file('config/elastic_search_user.yml').with_indifferent_access

# user.rb
class User < ActiveRecord::Base
  settings ElasticSearchSettingsForUser do
    mapping do
      [:name, :email, :company].each do |attribute|
        indexes attribute, type: 'string', analyzer: 'ngram_analyzer'
      end
    end
  end

  #...
end