How to update model relationships in ember?

I have many to many relationships in ember:

MYSPACE.User= Model.extend({
   teams: hasMany('team'),
});
MYSPACE.Team = Model.extend({
    users:       hasMany('user'),
});

On the user admin page you can update user teams - add new teams, remove teams etc ... So how I can update user teams?

Imagine you have user with teams with ids [2,3,4] and you update user to have teams [2,5,6,7]

We are using ember 1.6

How to do it?