update a3 to index

Author: lfangin

index.html

@@ -24,6 +24,11 @@
         Assignment #2: Fully-Connected Nets, BatchNorm, Dropout, ConvNets, Tensorflow/Pytorch
       </a>
     </div>
+    <div class="materials-item">
+      <a href="assignments2020/assignment3/">
+        Assignment #3: Image Captioning with Vanilla RNNs and LSTMs, Neural Net Visualization, Style Transfer, Generative Adversarial Networks
+      </a>
+    </div>
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     <div class="materials-item">
       <a href="assignments2019/assignment2/">