Selection in source and destination lists

I'm starting RoR and I have a similar situation to using GEM Cocoom, the difference is I already have the data in the two tables related. And I would like to work with selection between source and destination lists. I call it the shelf. I have in the menu of a pizzeria the type of pizza commercialized that in its assembly they use ingredients and these ingredients can be used in several types of pizza. I would like to know if there is a GEM that can make my life easier or if someone has an example of code they might be following.