Add datasets description notebooks

notebooks.json

@@ -68,7 +68,10 @@
     "notebooks/trees_ex_01.ipynb",
     "notebooks/trees_ex_02.ipynb",
     "notebooks/trees_hyperparameters.ipynb",
-    "notebooks/trees_regression.ipynb"
+    "notebooks/trees_regression.ipynb",
+    "datasets_california_housing.ipynb",
+    "datasets_ames_housing.ipynb",
+    "datasets_blood_transfusion.ipynb"
   ],
   "datasets": [
     "datasets/README.md",