Use SERIAL for users id field; general cleanup

src/Main.hs

@@ -20,31 +20,27 @@ import qualified Servant        as S
 --
 main :: IO ()
 main = do
-  pool <- createConnectionPool
+  pool   <- createConnectionPool 
   let env = AppEnv { pool = pool }
-  runEffStack env $ databaseInit
+  runAppEff env $ databaseInit
   run port . serve proxy $ app env
 
 app :: AppEnv -> Server AppAPI
-app env = transformEff env
-        $ rootHandler
-     :<|> userListHandler
-     :<|> userGetHandler
-     :<|> userPostHandler
-     :<|> userDeleteHandler
+app env = hoistServer proxy (Handler . ExceptT . runAppEff env) handlers
 
-transformEff :: AppEnv -> ServerT AppAPI AppEff -> ServerT AppAPI Handler
-transformEff env = hoistServer proxy
-  $ Handler
-  . ExceptT
-  . runEffStack env
+handlers :: ServerT AppAPI AppEff
+handlers = rootHandler
+      :<|> userListHandler
+      :<|> userGetHandler
+      :<|> userPostHandler
+      :<|> userDeleteHandler
 
-runEffStack :: AppEnv -> AppEff a -> IO (Either ServerError a)
-runEffStack env = runEff
-  . runErrorNoCallStack
-  . runReader env
-  . runDatabaseIO
-  . runLoggerPSQL
+runAppEff :: AppEnv -> AppEff a -> IO (Either ServerError a)
+runAppEff env = runEff
+              . runErrorNoCallStack
+              . runReader env
+              . runDatabaseIO
+              . runLoggerPSQL
 
 port :: Int
 port = 8080