updating installation notes

docs/source/howto/installation.rst

@@ -18,12 +18,20 @@ Install ToMoBAR as a pre-built conda Python package:
 
    $ conda install -c httomo tomobar
 
-or install with the main dependencies (preferably into a fresh environment):
+or install with the main dependencies into a new environment:
 
 .. code-block:: console
 
    $ conda install -c httomo -c conda-forge tomophantom tomobar astra-toolbox ccpi-regulariser pypwt
 
+Install ToMoBAR from PyPi:
++++++++++++++++++++++++++++
+One can install ToMoBAR from PyPi, however, not all dependencies might be at PyPi yet.
+
+.. code-block:: console
+
+   $ pip install tomobar
+
 Create conda environment:
 +++++++++++++++++++++++++
 Sometimes the one-liner above doesn't work. In that case we suggest creating a new conda environment,