Each platform defines a proper location for storing user configuration files as follows:
- Linux and other X11 systems store configuration files in a location defined in the $XDG_CONFIG_HOME environment variable, which defaults to ~/.config if it's not defined.
- macOS user config files are stored in ~/Library/Application Support/.
- Windows user config files are stored in %USERPROFILE%\AppData\Local. Though if your environment uses Active Directory (AD) with roaming profiles, you might prefer to use %HOME%\AppData\Roaming instead.
To realize this in our application, we'll edit our Application object to pass the correct path into SettingsModel. Remember that our SettingsModel constructor takes a path keyword argument ...
