Edited gitignore and README to make everything work proprely with virtualenv

.gitignore

 db.sqlite3
 *.pyc
 *__pycache__*
+.DS_Store
+env_sith

README.md

@@ -5,7 +5,10 @@ To start working on the project, just run the following commands:
 
     git clone https://ae-dev.utbm.fr/ae/Sith.git
     cd Sith
-    python3 manage.py migrate
+    virtualenv --clear --python=python3 env_sith
+    source env_sith/bin/activate
+    pip install -r requirements.txt
+    ./manage.py migrate
 
 To load some initial data in the core:
 
@@ -19,4 +22,4 @@ To start the debug server, just run `python3 manage.py runserver`
   * Django
 
 The development is done with sqlite, but it is advised to set a more robust
-DBMS for production (Postgresql for example)
\ No newline at end of file
+DBMS for production (Postgresql for example)

requirements.txt

+django