Update README.md

README.md

@@ -3,14 +3,18 @@
 # rhapsody
 Python program, based on Prody, for pathogenicity prediction of human missense variants.
 
-## Installation
+## Install using pip
 Rhapsody is published on [PyPI](https://pypi.org/). To install rhapsody, please use pip in the terminal:
 ```
 pip install -U rhapsody
 ```
 
-## To use a local ProDy package, use:
+## Install from source
+Rhapsody is written in pure Python so no local compilation is needed. To install from the source, you can download or clone rhapsody to your prefered location (e.g. `path/to/rhapsody/`), and then add that location to `PYTHONPATH` environmental variable. For example, on Linux you can add the following line to your `~/.bashrc`:
 ```
-import os, sys
-sys.path.insert(0, os.path.realpath( 'path/to/local/prody/package' ))
+EXPORT PYTHONPATH="path/to/rhapsody/:$PYTHONPATH"
 ```
+
+If you are running on Windows, please follow this tutorial:
+[How to add to the PYTHONPATH in Windows, so it finds my modules/packages? - stackoverflow](https://stackoverflow.com/a/4855685)
+