Update README.md

Author: dingran

README.md

@@ -167,13 +167,21 @@ Material on these topics are widely available elsewhere, so we will just cite th
     - SVM
     - generative vs descriptive models
         - Gaussian mixture, Naive bayes
+- Optimization algorithms
+    - gradient descent, sgd and other popular variants (RMSProp, Adagrad, Adam etc)
+    - EM algorithm
 - Learning theory
     - bias vs variance
     - feature selection
     - model validation
     - model metrics
     - ensemble method, boosting, bagging
 - Deep learning topics
+    - feedforward networks
+    - backprop
+    - cnn
+    - rnn/lstm/gru
+    - dropout, batchnorm