[feature request] - ability to create collections

[greendingbat]

EmulationStation has this feature, and it's very useful. These collections could be created as a widget, then games could be added to them. This would allow people to create things like "Best 100 NES Games" or "Zelda Franchise" collections.

Behind the scenes, this would just need to be a list of references to the roms.

Thank you so much for your work, the app is amazing!