adding tutorial 23 (#666)

docs/source/_tutorial.rst

@@ -40,5 +40,6 @@ Supervised Learning
 - `Introductory Tutorial: Supervised Learning with PINA  <tutorial20/tutorial.html>`_
 - `Chemical Properties Prediction with Graph Neural Networks <tutorial15/tutorial.html>`_
 - `Reduced Order Model with Graph Neural Networks for Unstructured Domains <tutorial22/tutorial.html>`_
+- `Data-driven System Identification with SINDy <tutorial23/tutorial.html>`_
 - `Unstructured Convolutional Autoencoders with Continuous Convolution <tutorial4/tutorial.html>`_
 - `Reduced Order Modeling with POD-RBF and POD-NN Approaches for Fluid Dynamics <tutorial8/tutorial.html>`_