DB: If no workflow exists, add a dummy one

migrations/507_2022-10-16_workflow.model

@@ -0,0 +1,5 @@
+Workflow
+    ident  WflIdent
+    name   Text          Maybe
+    desc   Text          Maybe
+    scope  WorkflowScope

src/Vervis/Migration.hs

@@ -2798,6 +2798,12 @@ changes hLocal ctx =
     , removeField "LocalMessage" "author"
       -- 506
     , renameField "LocalMessage" "authorNew" "author"
+      -- 507
+    , unchecked $ lift $ do
+        mw <- selectFirst ([] :: [Filter Workflow507]) []
+        when (isNothing mw) $
+            insert_ $
+                Workflow507 (text2wfl "dummy507") Nothing Nothing WSPublic
     ]
 
 migrateDB

src/Vervis/Migration/Model.hs

@@ -679,3 +679,6 @@ makeEntitiesMigration "498"
 
 makeEntitiesMigration "504"
     $(modelFile "migrations/504_2022-10-16_message_author.model")
+
+makeEntitiesMigration "507"
+    $(modelFile "migrations/507_2022-10-16_workflow.model")