No instance for (Control.Monad.Trans.Resource.MonadResource IO)
  arising from a use of `selectList'
Possible fix:
  add an instance declaration for
  (Control.Monad.Trans.Resource.MonadResource IO)
In a stmt of a 'do' block:
  oneJohnPost <- selectList [BlogPostAuthorId ==. johnId] [LimitTo 1]
In the second argument of `($)', namely
  `do { runMigration migrateAll;
        johnId <- insert $ Person "John Doe" $ Just 35;
        janeId <- insert $ Person "Jane Doe" Nothing;
        insert $ BlogPost "My fr1st p0st" johnId;
        .... }'
In the second argument of `($)', namely
  `runSqlConn
   $ do { runMigration migrateAll;
          johnId <- insert $ Person "John Doe" $ Just 35;
          janeId <- insert $ Person "Jane Doe" Nothing;
          insert $ BlogPost "My fr1st p0st" johnId;
          .... }'

{-# LANGUAGE QuasiQuotes, TemplateHaskell, TypeFamilies, OverloadedStrings #-}
{-# LANGUAGE GADTs, FlexibleContexts #-}
import Database.Persist
import Database.Persist.Sqlite
import Database.Persist.TH
import Control.Monad.IO.Class (liftIO)

share [mkPersist sqlSettings, mkMigrate "migrateAll"] [persist|
Person
    name String
    age Int Maybe
    deriving Show
|]

main :: IO ()
main = withSqliteConn "test.db" $ runSqlConn $ do
    runMigration migrateAll
    -- johnId <- insert $ Person "John Doe" $ Just 35
    -- liftIO $ print johnId