doc for install and synchronization

docs/source/installation/prod-calendar-sms-sending.rst

@@ -0,0 +1,27 @@
+
+Send short messages (SMS) with calendar bundle
+==============================================
+
+To activate the sending of messages, you should run this command on a regularly basis (using, for instance, a cronjob):
+
+.. code-block:: bash
+
+   bin/console chill:calendar:send-short-messages
+
+A transporter must be configured for the message to be effectively sent. 
+
+Configure OVH Transporter
+-------------------------
+
+Currently, this is the only one transporter available.
+
+For configuring this, simply add this config variable in your environment:
+
+```env
+SHORT_MESSAGE_DSN=ovh://applicationKey:applicationSecret@endpoint?consumerKey=xxxx&sender=yyyy&service_name=zzzz
+```
+
+In order to generate the application key, secret, and consumerKey, refers to their `documentation <https://docs.ovh.com/gb/en/api/first-steps-with-ovh-api/>`_.
+
+Before to be able to send your first sms, you must enable your account, grab some credits, and configure a sender. The service_name is an internal configuration generated by OVH.
+