{-# LANGUAGE KindSignatures #-}
{-# LANGUAGE ExistentialQuantification #-}
{-# LANGUAGE StandaloneDeriving #-}
{-# LANGUAGE DeriveAnyClass #-}

import Data.Monoid
import Data.Kind
import Data.Functor.Identity

data Logger = LFile | LStdout deriving Show

data Database = DPG | DMem deriving Show

data App (m :: Type -> Type) = App
  { _logger :: m Logger
  , _db     :: m Database
  }

deriving instance forall m a. Monoid (m a) => Monoid (App m)