postman pre script

pm.sendRequest({
    url: 'http://localhost:3000/api/v1/users/sign_in',
    method: 'POST',
    header: 'content-type:application/json',
    body: {
        mode: 'raw',
        raw: JSON.stringify({ user: {
            email: 'abcd@gmail.com',
            password: "abcdef"
        }})
    }
}, function (err, res, xhr) {
    
    var token = res.headers.get('authorization');
    console.log(token);
    pm.globals.set("token", token);
});