Update 'README.md'

README.md

@@ -1,3 +1,29 @@
 # huffman-py
 
-Huffman algorithm implementation in Python with a QT GUI.
+Huffman algorithm implementation in Python with a QT GUI.
+
+## Installation :  
+Graphviz must be installed on host system. (see https://graphviz.org/download/)    
+Don't forget to include dot executable in your PATH. (File is often there: /usr/local/bin/dot)
+
+huffman-py installation:
++ preferred method:
+``` 
+cd <path to cloned git>
+pip install .
+```
++ alternative method:
+```
+cd <path to cloned git>
+python setup.py build
+python setup.py install
+```  
+Will create a huffman_py file to run the application. (Should be in ~/.local/bin)
+  
+  
+## checks:
+to run unit tests:
+``` 
+cd <path to cloned git>
+python -m unittest discover
+```