Type in console:

obj = ' { "list" : {"id" : 1, "name" : "Nome", "users" : [1,2] }, "users": [{ "id":1, "username": "user1", "users": 1 },{ "id":2, "username":"user2", "users" : 1}] } ';
obj = JSON.parse(obj);
DS.get('defaultStore').load( App.List, obj);

var l_len = App.List.find().get('length');
var u_len = App.User.find().get('length');
console.log( ">>>>>>>  "+ l_len + "record(s) " +u_len + "record(s)");

payload of `obj` variable (indented)

{ 
    "list" : { "id": 1, "name" : "Nome", "users" : [1,2] },
    "users": [
                     { "id": 1, "username": "user1", "users": 1 },
                     { "id": 2, "username": "user2", "users": 1 }
             ]

}