I am developing multiple websites based on Yii2 framework and I was wondering if there is any good way or if it's even good idea or not to create a shared basic config `main.php` file. 

The reason behind this is that all my projects are based on same system, have a lot of similarities and I simply want to keep things DRY. Configs are also mostly same - the only differences actually are database names and few other values. Even urlManager rules are not so different. 

The problem is that when for example I would want to add additional `FileTarget` to logger targets for all websites I have to do this for each project separately and I can never be sure if all project configs are up to date and have everything set up properly.

So I was wondering if there is any Yii way of creating default config file shared in multiple projects or if it's simply a bad idea. For example I could create bootstrap component which sets defaults or add default config as first item in the list of merged configs in `frontend\web\index.php` file. I have private packages added in composer so it's not a problem adding file that will be shared in all projects.