Mine

config_file = "#{Rails.root}/config/mongodb.local.yml"config_file.gsub!(/\.local/, "") if !File.exist?(config_file)db_config = YAML::load(File.read(config_file))if db_config[Rails.env] && db_config[Rails.env]['adapter'] == 'mongodb'  mongo  = db_config[Rails.env]  logger = ENV['LOG_MONGO'] ? Rails.logger : nil   if ENV['REPLICA_SET_NAME']    MongoMapper.connection = Mongo::ReplSetConnection.new(*ENV['REPLICA_HOSTS', :read_secondary => true, :logger => logger, :rs_name => ENV['REPLICA_SET_NAME']  else    mongo['hostname'] = ENV['MONGODB_HOST'] if ENV['MONGODB_HOST']    MongoMapper.connection = Mongo::Connection.new(mongo['hostname'], 27017, :logger => logger)  end   MongoMapper.database  = mongo['database']end  Delayed::Worker.backend = :mongo_mapperrequire 'lib/bson_ordered_hash'