I have a site with a tagging system but would like to enable users to be able to subscribe to different sets of tags of their choice so that when a new submission is made and has tags that match what the user is subscribed to they get a notification. For example, say a user is only interested in red, wallpapers that are considered large. They would add those three tags to a set and when a wallpaper is added that contains those tags the user gets a notification. They would need to be able to do this with any set of tags. It seems like a tricky problem, and I can't seem to come up with a simple solution. Does anyone know if this is already solved in a Gem somewhere, or have any ideas on how to do it efficiently?
Thanks for looking