quick dev installation instructions

README.rst

@@ -29,3 +29,21 b' You can run IPython from this directory without even installing it system-wide'
 by typing at the terminal::
 
    $ python ipython.py
+
+
+Development installation
+========================
+
+If you want to hack on certain parts, e.g. the IPython notebook, in a clean
+environment (such as a virtualenv) you can use ``pip`` to grab the necessary
+dependencies quickly::
+
+   $ pip install -e .[notebook]
+
+This installs the necessary packages and symlinks IPython into your current
+environment so that you can work on your local repo copy and run it from anywhere::
+
+   $ ipython notebook
+
+The same proces applies for other parts, such as the qtconsole (the
+``extras_require`` attribute in the setup.py file lists all the possibilities).