yesod-1.1.0: scaffold/mongoDBConnPool.cg
withConnectionPool :: (MonadControlIO m, Applicative m) => AppConfig DefaultEnv -> (ConnectionPool -> m b) -> m b
withConnectionPool conf f = do
dbConf <- liftIO $ loadMongo (appEnv conf)
withMongoDBPool (mgDatabase dbConf) (mgHost dbConf) (mgPoolSize dbConf) f