let the function get the time itself

src/Main.hs

@@ -184,9 +184,8 @@ userList muid ref = do
 productNew :: Maybe Int -> ProductSubmit -> MateHandler Int
 productNew (Just _) bevsub = do
   conn <- rsConnection <$> ask
-  now <- liftIO $ getCurrentTime
   bevid <- insertProduct bevsub conn
-  void $ insertNewEmptyAmount bevid now bevsub conn
+  void $ insertNewEmptyAmount bevid bevsub conn
   return bevid
 productNew Nothing _ =
   throwError $ err403

src/Model/Amount.hs

@@ -56,12 +56,13 @@ amountTable = table "amount" (
 
 insertNewEmptyAmount
   :: Int           -- | the associated product id
-  -> UTCTime       -- | current time
   -> ProductSubmit -- | submitted product data
   -> PGS.Connection
   -> MateHandler Int
-insertNewEmptyAmount bevid now (ProductSubmit _ price _ _ _ _ _ _ _) conn =
+insertNewEmptyAmount bevid (ProductSubmit _ price _ _ _ _ _ _ _) conn =
-  fmap head $ liftIO $ runInsert_ conn $ Insert
+  liftIO $ do
+    now <- getCurrentTime
+    fmap head $ runInsert_ conn $ Insert
       { iTable = amountTable
       , iRows  =
         [