monad-persist 
This module provides an mtl-style MonadPersist typeclass for persistent, as well as a PersistT monad transformer that implements it. This makes it easier to use persistent in an arbitrary monad transformer stack, rather than one that must be ReaderT over MonadIO.
import Control.Monad.Logger (runNoLoggingT)
import Control.Monad.Persist
import Data.Text (Text)
import Database.Persist.Sqlite (withSqliteConn)
import Database.Persist.TH
share [mkPersist sqlSettings, mkMigrate "migrateAll"] [persistLowerCase|
User
name Text
email Text
UniqueEmail email
deriving Eq Show
|]
ghci> runNoLoggingT $ withSqliteConn ":memory:" $ \conn -> flip runSqlPersistT conn $ do
runMigration migrateAll
insert_ User { userName = "Alyssa", userEmail = "alyssa@example.com" }
users <- selectList [] []
return (users :: [Entity User])
Migrating: CREATE TABLE "user"("id" INTEGER PRIMARY KEY,"name" VARCHAR NOT NULL,"email" VARCHAR NOT NULL,CONSTRAINT "unique_email" UNIQUE ("email"))
[Entity {entityKey = UserKey {unUserKey = SqlBackendKey {unSqlBackendKey = 1}}, entityVal = User {userName = "Alyssa", userEmail = "alyssa@example.com"}}]
