Remove nbextensions from installation instructions, fixes ageron#401

README.md

@@ -98,21 +98,11 @@ Next, use pip to install the required python packages. If you are not using virt
 Great! You're all set, you just need to start Jupyter now.
 
 ## Starting Jupyter
-If you want to use the Jupyter extensions (optional, they are mainly useful to have nice tables of contents), you first need to install them:
-
-    $ jupyter contrib nbextension install --user
-
-Then you can activate an extension, such as the Table of Contents (2) extension:
-
-    $ jupyter nbextension enable toc2/main
-
 Okay! You can now start Jupyter, simply type:
 
     $ jupyter notebook
 
-This should open up your browser, and you should see Jupyter's tree view, with the contents of the current directory. If your browser does not open automatically, visit [localhost:8888](http://localhost:8888/tree). Click on `index.ipynb` to get started!
-
-Note: you can also visit [http://localhost:8888/nbextensions](http://localhost:8888/nbextensions) to activate and configure Jupyter extensions.
+This should open up your browser, and you should see Jupyter's tree view, with the contents of the current directory. If your browser does not open automatically, visit [127.0.0.1:8888](http://127.0.0.1:8888/tree). Click on `index.ipynb` to get started!
 
 Congrats! You are ready to learn Machine Learning, hands on!
 

index.ipynb

@@ -60,10 +60,7 @@
     "### To run the examples\n",
     "* **Jupyter** – These notebooks are based on Jupyter. If you just plan to read without running any code, there's really nothing more to know, just keep reading! But if you want to experiment with the code examples you need to:\n",
     "    * follow the [installation instructions](https://github.com/ageron/handson-ml/#installation),\n",
-    "    * learn how to use Jupyter. Start the User Interface Tour from the Help menu.\n",
-    "\n",
-    "### To activate extensions\n",
-    "* If this is an interactive session (see above), you may want to turn on a few Jupyter extensions by going to the [Extension Configuration](../nbextensions/) page. In particular the \"*Table of Contents (2)*\" extension is quite useful.\n"
+    "    * learn how to use Jupyter. Start the User Interface Tour from the Help menu."
    ]
   },
   {
@@ -92,7 +89,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.6.6"
+   "version": "3.6.8"
   },
   "nav_menu": {},
   "toc": {