jQuery - Create an array of objects using each

I'm a jQuery newbie.

I have a simple form with n lines (although I'm not using html form):

<div id="myCities">
  <div class="line">City1: <input type="text" /></div>
  <div class="line">City2: <input type="text" /></div>
  <div class="line">City3: <input type="text" /></div>
  <button>Add Your Cities</button>
</div>

I have a javascript var called "users" with general users data:

var users = [
  { "username": "John", "year": 1999},
  more users...
]

When clicking on the button, I want to add an array of cities to the user's data (let's say we are working with John so he's [0])

I want the object to look like:

{ "username": "John",
  "year": 1999,
  "cities": [
    { "City1": $('.line input).val() },
    ... and so on for the 3 cities entered
  ]   
}

I tried using

$.each($('.line'), function() { 
   // but I'm not really sure what to put here 
});

Thanks!