Harden mutation admission and storage observation

app/Main.hs

@@ -15,7 +15,7 @@ import           Nuthatch
 import           Nuthatch.Db (migrate, query_, withDb)
 import           Nuthatch.Redis (withRedis)
 import           Nuthatch.S3 (newS3)
-import           System.Directory (doesFileExist)
+import           System.Directory (doesDirectoryExist)
 import           System.FilePath ((</>))
 import           System.IO (BufferMode (LineBuffering), hSetBuffering, stdout)
 
@@ -62,14 +62,14 @@ waitForPostgres cfg = go (60 :: Int)
 findSchema :: IO FilePath
 findSchema = do
   let candidates =
-        [ "sql" </> "001_schema.sql"
-        , ".." </> "sql" </> "001_schema.sql"
-        , "/app/sql" </> "001_schema.sql"
+        [ "sql"
+        , ".." </> "sql"
+        , "/app/sql"
         ]
-  existing <- mapM (\p -> doesFileExist p >>= \e -> pure (e, p)) candidates
+  existing <- mapM (\p -> doesDirectoryExist p >>= \e -> pure (e, p)) candidates
   pure $ case [p | (True, p) <- existing] of
     (p : _) -> p
-    []      -> "sql/001_schema.sql"
+    []      -> "sql"
 
 readHost :: String -> HostPreference
 readHost = fromString