ManyToManyRelation

[zanzara]

It's driving me mad.
I got two simple tables (users and groups) which has a ManyToManyRelation relation.
How can i do an insert?
How must the app.service('/users').create({...}) and app.service('/groups').create({...}) look like, that can insert a new user with a new group??? (The group table has only one item "name")
This is my relationMappings (the other one is similar, but id's are swapped):

  static get relationMappings() {
    const Groups = require('./groups.model')();
    return {
      group: {
          relation: Model.ManyToManyRelation,
          modelClass: Groups,
          join: {
              from: 'users.id',
              through: {
                from: 'users_groups.user_id',
                to: 'users_groups.group_id'
              },
              to: 'groups.id'
          }
        }
    }
  }

Appreciating really any help!