Save Transformer module in root when training with ST (#50)

- Save the Transformer module in the root for easier loading (2e1536ace112a8f74bde5b43b2fe5644bc1426f7)

custom_st.py

@@ -33,6 +33,8 @@ class Transformer(nn.Module):
             None, then model_name_or_path is used
     """
 
+    save_in_root: bool = True
+
     def __init__(
         self,
         model_name_or_path: str,