var Company = sequelize.define({
 company_graphdb_id: {...},
 company_id: {..}
})

var User = sequelize.define({
  user_graphdb_id: {...}
  user_id: {...}
});

//Now when i define the relationsships
Company.hasMany(User);
//This gives me the ability to do
companyInstance.addUser(userInstance);

//What i want to do is, in my custom addUser() do something like
function myCustomAddUser(userInstance){
   var userNode = graphDB.insertNode({userInstance...});
   graphDB.insertrelationsShip(userNode, graphDB.getNode(company.company_graphdb_id));
   return company.addUser(userInstance);
}