Improvement of README.

README.md

@@ -2,8 +2,48 @@
 
 This tool can be used to retrieve informations from the site _https://www.espace-citoyens.net/_ used by some cities to manage their relationship with citizens.
 A quick search on Google shows that is used by:
+
     - Rennes
     - Vannes
+    - Brest
     - Asnières sur Seine
 
 # Usage
+
+Preparation of a virtual environment for the script:
+```
+python3 -m venv venv
+source ./venv/bin/activate
+pip3 install -r requirements.txt
+deactivate
+```
+
+The to use the command:
+```
+source venv/bin/activate
+./citoyen.py -h 
+deactivate
+```
+This will display the help.
+
+```
+source venv/bin/activate
+./citoyen.py -l [login] -p [password] -C [city] -A
+deactivate
+```
+This will test the authentication.
+
+```
+source venv/bin/activate
+./citoyen.py -l [login] -p [password] -C [city] -L
+deactivate
+```
+This will list the kind of reservations.
+
+```
+source venv/bin/activate
+./citoyen.py -l [login] -p [password] -C [city] -D -i [index] -o file.ics
+deactivate
+```
+This will dump the ith kind of reservation (in the order obtained by _L_ command) into a ICS file.
+