wip: Radicale extension.

Initial documentation.
see #574

doc/index.rst

@@ -29,6 +29,7 @@ Plugins
    plugins/postfix_relay_domains
    plugins/amavis
    plugins/statistics
+   plugins/radicale
    plugins/postfix_autoreply
    plugins/sievefilters
    plugins/webmail

doc/plugins/radicale.rst

@@ -0,0 +1,39 @@
+#################
+Radicale frontend
+#################
+
+This plugin provides a simple management frontend for `Radicale
+<http://radicale.org/>`_, a complete CalDAV (calendar) and CardDAV
+(contact) server solution.
+
+Features currently supported are:
+
+* Private calendar creation (available for simple users)
+* Rights management for private calendars
+* Shared calendar creation by domain (available for domain administrators)
+
+.. note::
+
+   This plugin requires Radicale 0.9 or higher.
+
+Setup
+=====
+
+Once `Radicale is installed
+<http://radicale.org/user_documentation/>`_ on your server, you must
+tell Modoboa where it can find the file used to store rules.
+
+Go to the *Modoboa > Parameters > Radicale* panel and fill the
+**Radicale rights file path** setting (an absolute path is required).
+
+When the configuration is done, Modoboa will completly handles the
+file's content. It means every manual modification you could made on
+this file would be overriden.
+
+To do so, a new cron job must be created. You can use the following
+example::
+
+  */2 * * * * <modoboa_site>/manage.py generate_rights
+  #
+  # Or like this if you use a virtual environment:
+  # */2 * * * * <virtualenv path/bin/python> <modoboa_site>/manage.py generate_rights