Add property to every object in array.md

Description:

Your task is to add a new property usersAnswer to every object in the array questions. The value of usersAnswer should be set to null. The solution should work for array of any length.

After adding the property the result should be:

Examples (input --> output):

var questions = [{
    question: "What's the currency of the USA?",
    choices: ["US dollar", "Ruble", "Horses", "Gold"],
    corAnswer: 0,
    usersAnswer: null
}, {
    question: "Where was the American Declaration of Independence signed?",
    choices: ["Philadelphia", "At the bottom", "Frankie's pub", "China"],
    corAnswer: 0,
    usersAnswer: null
}];

Solution:

questions.forEach(question => question['usersAnswer'] = null);