cal: basic README added

cal/LICENSE

@@ -5,7 +5,7 @@ of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is
- furnished to do so, subject to the following conditions:
+furnished to do so, subject to the following conditions:
 
 The above copyright notice and this permission notice shall be included in
 all copies or substantial portions of the Software.

cal/README.md

@@ -0,0 +1,27 @@
+Calendar Export
+===============
+
+This addon makes it possible to export the events posted by your users being
+exported to other formats, so they can be imported into other calendar
+applications.
+
+Exporting a calendar is an _opt-in_ feature which has to be activated by each
+of the users in the _addon settings_. As the admin you can only provide the
+service but should not force it upon your users.
+
+The calendars are exported at
+
+	http://example.com/cal/username/format
+
+currently the only supported format is __ical__.
+
+Author
+------
+
+This addon is developed by [Tobias Diekershoff](https://f.diekershoff.de/profile/tobias).
+
+License
+-------
+
+This addon is licensed under the [MIT](http://opensource.org/licenses/MIT)
+license, see also the LICENSE file in the addon directory.