Experimental: don't try to marshal if we don't care

Also explicitly test migration during deployment

db.hs

@@ -24,12 +24,14 @@ import Data.Time
 
 
 data DBAction = DBClear
+              | DBMigrate
               | DBFill
 
 argsDescr :: [OptDescr DBAction]
 argsDescr =
-  [ Option ['c'] ["clear"] (NoArg DBClear) "Delete everything accessable by the current database user"
-  , Option ['f'] ["fill"]  (NoArg DBFill)  "Fill database with example data"
+  [ Option ['c'] ["clear"]   (NoArg DBClear)   "Delete everything accessable by the current database user"
+  , Option ['m'] ["migrate"] (NoArg DBMigrate) "Perform database migration"
+  , Option ['f'] ["fill"]    (NoArg DBFill)    "Fill database with example data"
   ]
 
   
@@ -38,11 +40,12 @@ main = do
   args <- map unpack <$> getArgs
   case getOpt Permute argsDescr args of
     (acts@(_:_), [], []) -> forM_ acts $ \case
-      DBClear -> runStderrLoggingT $ do -- We don't use `db` here, since we do /not/ want any migrations to run, yet
+      DBClear   -> runStderrLoggingT $ do -- We don't use `db` here, since we do /not/ want any migrations to run, yet
         settings <- liftIO getAppDevSettings
         withPostgresqlConn (pgConnStr $ appDatabaseConf settings) . runSqlConn $ do
           rawExecute "drop owned by current_user;" []
-      DBFill -> db $ fillDb
+      DBMigrate -> db $ return ()
+      DBFill    -> db $ fillDb
     (_, _, errs) -> do
       forM_ errs $ hPutStrLn stderr
       hPutStrLn stderr $ usageInfo "db.hs" argsDescr

src/Model/Migration.hs

@@ -158,6 +158,6 @@ customMigrations = Map.fromListWith (>>)
 tableExists :: MonadIO m => Text -> ReaderT SqlBackend m Bool
 tableExists table = do
   haveSchoolTable <- [sqlQQ| SELECT to_regclass(#{table}); |]
-  case haveSchoolTable :: [Maybe (Single Text)] of
+  case haveSchoolTable :: [Maybe (Single PersistValue)] of
     [Just _] -> return True
     _other   -> return False