There's a few red flags I see.

1. Your config syntax of `$data['dev.*']` will only work if you're actually `return $data` at the end of your config file.  You only posted a snippet, so I'm not sure if you're doing that.

2. I assume `'dev.*'` is for [multi-environment][1] aware config settings, but a wildcard (`*`) is only supported as the first element in the array and is used to tell Craft that this is a multi-environment config.

3. `'cache' => true,` There is no [config setting][2] called `cache`.

Finally:

    2015/12/09 15:42:38 [error] [exception.Error] Error: Class 'Twig_Cache_Filesystem' not found in /home/forge/staging.domain.com/releases/20151209154140/craft/app/vendor/twig/twig/lib/Twig/Environment.php:263

That indicates that Craft is missing some of its files.  Try re-uploading your `craft/app` folder with a fresh copy downloaded from https://craftcms.com.


  [1]: https://craftcms.com/docs/multi-environment-configs
  [2]: https://craftcms.com/docs/config-settings