Add the following to your Gemfile then refresh your dependencies by executing "bundle install" (or just simple "bundle"): gem "mongodb_logger" or install by rubygems gem install mongodb_logger Add adapter in Gemfile. Supported mongo and moped (mongoid). For example: gem "mongo" gem "bson_ext" # for MRI or gem "moped" Add the following line to your ApplicationController: include MongodbLogger::Base