readme: communities implementation

README.md

@@ -18,6 +18,7 @@ To install Hubl, you'll need:
 Before diving in you have to check your Hubl Server supports the following LDP packages:
 
 * djangoldp_account
+* djangoldp_community
 * djangoldp_notification
 * djangoldp_profile
 * djangoldp_skill
@@ -91,6 +92,16 @@ Where:
 * `authority` is the OpenID Provider. Usually, if you use `djangoldp-account` it's the same as your djangoldp server.
 * `endpoints.users` is the API endpoints for Users on your djangoldp server.
 
+### Communities
+
+Communities are mandatory to have an Hubl. If you're upgrading an existion Hubl, you can assign all your local users to a community this way:
+
+```bash
+./manage.py create_community --name="My community"
+```
+
+Don't forget to set some users as admin from the Django Admin if you want to allow them to create new users from app.
+
 ### Optional personalisation
 
 On `config.json`: