Dependencies
------------
1. Make sure you have python3 installed
2. Install the nltk package for python3
3. Install the stemmer package
4. Install nltk data (packages required are punkt and stopwords)

Instructions for Debian / Ubuntu :
$ sudo su -
# apt-get install python3 python3-setuptools python3-stemmer
# easy_install3 pip
# pip3 install nltk
# python3 -m nltk.downloader -d /usr/share/nltk_data punkt stopwords

Testing the program
-------------------
1. Make sure you have all the dependencies installed
2. Extract the archive in Sujet/20_newgroups.tar.gz into Sujet/
3. Launch ./ng-test.py from the project folder