Symfony form, collection of new entity and entity type together

this si my first question here. I've searched a lot and i haven't found any solution. I have 2 entities in symfony, User and Tags, each user is in a relation with many tags. In my user's form i want to be able to select one or more tag and to create new ones. How can i achieve this? I've read how to select One tag or create a new One but this isn't what i want.