The purpose of this post is to let anyone quickly find how to accomplish a configuration task, and list here all the posibilities of the config.php file and also link to pages that explain how is each thing implemented.
A simple and effective way to keep track what your users are doing within your application is to log their activities related to database modifications. You can log whenever a record was inserted, changed or deleted, and also when and by which user this was done. For a CActiveRecord Model you could use a behavior for this purpose. This way you will be able to add log functionality to ActiveRecords very easily.