update install docs

Signed-off-by: Kenneth Reitz <[email protected]>

Author: kennethreitz

docs/install.rst

@@ -198,41 +198,6 @@ Congratulations, you now know how to install and use Python packages! ✨ 🍰 
 
 .. _proper_installation:
 
-☤ Fancy Installation of Pipenv
-==============================
-
-To install pipenv in a fancy way, we recommend using `pipsi <https://github.com/mitsuhiko/pipsi>`_.
-
-Pipsi is a powerful tool which allows you to install Python scripts into isolated virtual environments.
-
-To install pipsi, first run this::
-
-    $ curl https://raw.githubusercontent.com/mitsuhiko/pipsi/master/get-pipsi.py | python
-
-Follow the instructions, you'll have to update your ``PATH``.
-
-Then, simply run::
-
-    $ pipsi install pew
-    $ pipsi install pipenv
-
-To upgrade pipenv at any time::
-
-    $ pipsi upgrade pipenv
-
-
-This will install both ``pipenv`` and ``pew`` (one of our dependencies) in an isolated virtualenv, so it doesn't interfere with the rest of your Python installation!
-
-.. _more_proper_installation:
-
-☤ Referentially Transparent Installation of Pipenv
-==================================================
-
-Nix provides atomic upgrades and rollbacks, it's reliable and reproducible thanks to keeping all dependencies isolated all the way down to libc.
-
-`Once installed <https://nixos.org/nix/>`_ simply run::
-
-    $ nix-env --install --attr pipenv
 
 ☤ Homebrew Installation of Pipenv
 =================================