add USB tutorial to index

Author: Hhhhhhao

index.rst

@@ -142,6 +142,13 @@ What's new in PyTorch tutorials?
    :link: intermediate/spatial_transformer_tutorial.html
    :tags: Image/Video
 
+.. customcarditem::
+   :header: Semi-Supervised Learning Tutorial Based on USB
+   :card_description: Learn how to train semi-supervised learning algorithms (on custom data) using USB and PyTorch.
+   :image: _static/img/usb_semisup_learn/code.png
+   :link: advanced/usb_semisup_learn.html
+   :tags: Image/Video
+
 .. Audio
 
 .. customcarditem::