Rewrite ticketFollowers migration without insertKey, it causes problems

src/Vervis/Migration.hs

@@ -62,8 +62,8 @@ defaultTime = UTCTime (ModifiedJulianDay 0) 0
 withPrepare :: Monad m => Mig m -> Apply m -> Mig m
 withPrepare (validate, apply) prepare = (validate, prepare >> apply)
 
-withPrePost :: Monad m => Apply m -> Mig m -> Apply m -> Mig m
-withPrePost pre (validate, apply) post = (validate, pre >> apply >> post)
+--withPrePost :: Monad m => Apply m -> Mig m -> Apply m -> Mig m
+--withPrePost pre (validate, apply) post = (validate, pre >> apply >> post)
 
 changes :: MonadIO m => [Mig m]
 changes =
@@ -212,22 +212,17 @@ changes =
       -- 50
     , addEntities model_2019_03_30
       -- 51
-    , let fsidTemp = fromBackendKey defaultBackendKey :: Key FollowerSet2019
-      in  withPrePost
-            (lift $ insertKey fsidTemp FollowerSet2019)
-            (addFieldRefRequired
-                "Ticket"
-                (toBackendKey fsidTemp)
-                "followers"
-                "FollowerSet"
-            )
-            (lift $ do
-                tids <- selectKeysList ([] :: [Filter Ticket2019]) []
-                for_ tids $ \ tid -> do
-                    fsid <- insert FollowerSet2019
-                    update tid [Ticket2019Followers =. fsid]
-                delete fsidTemp
-            )
+    , addFieldRefRequired'
+        "Ticket"
+        FollowerSet2019
+        (Just $ do
+            tids <- selectKeysList ([] :: [Filter Ticket2019]) []
+            for_ tids $ \ tid -> do
+                fsid <- insert FollowerSet2019
+                update tid [Ticket2019Followers =. fsid]
+        )
+        "followers"
+        "FollowerSet"
       -- 52
     , addUnique "Ticket" $ Unique "UniqueTicketFollowers" ["followers"]
       -- 53

src/Vervis/Migration/Model.hs

@@ -34,7 +34,6 @@ module Vervis.Migration.Model
     , model_2019_03_19
     , model_2019_03_30
     , FollowerSet2019Generic (..)
-    , FollowerSet2019
     , Ticket2019
     , model_2019_04_11
     )