fix deserialize

src/grung/types.py

@@ -298,7 +298,7 @@ class FilePointer(Field):
     def deserialize(self, value: str, db: TinyDB, recurse: bool = True) -> value_type:
         if not value:
             return None
-        return (db.path / value).read_bytes()
+        return (db.path / str(value)).read_bytes()
 
     def before_insert(self, value: value_type, db: TinyDB, record: Record) -> None:
         relpath = self.relpath(record)