try{
    var db = connect('admin');
    if(db.system.users.find({'user':'esb'}).count() == 0){
        print('Ready to addUser...');
	db.createUser({user: "esb",pwd: "esb",roles: [ { role: "userAdminAnyDatabase", db: "admin" } ]})
    }else{
        print('Already exist user.')
    }
}catch(err){
    print('Error occured:' + err);
}