Add jupyter notebook tutorials using Google Colaboratory (#599)

docs/index.rst

@@ -94,6 +94,7 @@ Tianshou is still under development, you can also check out the documents in sta
    :maxdepth: 1
    :caption: Tutorials
 
+   tutorials/get_started
    tutorials/dqn
    tutorials/concepts
    tutorials/batch

docs/spelling_wordlist.txt

@@ -147,3 +147,6 @@ mse
 gail
 airl
 ppo
+Jupyter
+Colab
+Colaboratory

docs/tutorials/get_started.rst

@@ -0,0 +1,13 @@
+Get Started with Jupyter Notebook
+=================================
+
+In this tutorial, we will use Google Colaboratory to show you the most basic usages of common building blocks in Tianshou. You will be guided step by step to see how different modules in Tianshou collaborate with each other to conduct a classic DRL experiment (PPO algorithm for CartPole-v0 environment).
+
+- L0:  `Overview <https://colab.research.google.com/drive/1yavOkfSTbyBD24-dyQzdETFN9YA7ioor?usp=sharing>`_
+- L1:  `Batch <https://colab.research.google.com/drive/1uklagjDxYjJERS9gJvgbPnV1BtMuXvOR?usp=sharing>`_
+- L2:  `Replay Buffer <https://colab.research.google.com/drive/1sfw-dDy02Gado-WuYlHAQsyWhZ33D1bd?usp=sharing>`_
+- L3:  `Vectorized Environment <https://colab.research.google.com/drive/1ABk2BgjzvC4DZu1rDxGzd2Uqjo3FRLEy?usp=sharing>`_
+- L4:  `Policy <https://colab.research.google.com/drive/1MhzYXtUEfnRrlAVSB3SR83r0HA5wds2i?usp=sharing>`_
+- L5:  `Collector <https://colab.research.google.com/drive/1CvOTPiNXdSST04I75Wuyvy_hZ949zKHZ?usp=sharing>`_
+- L6:  `Trainer <https://colab.research.google.com/drive/1qMsEiZZ8mh60ycbfoX-nYy6qMCnLkmZE?usp=sharing>`_
+- L7:  `Experiment <https://colab.research.google.com/drive/1CieGncgbGCt2grx8Mzwb7YTmFB0AGJ0f?usp=sharing>`_