title: AngularFire2 map date to timestamp and vice versa
body: <p>I have an object which contains a date. I want to save my dates as a timestamp. How I map the date to a timestamp when saving and converting it to a date when retrieving?</p>
  
  <pre><code>export class MyObject{
      date: Date;
  }
  
  let myDate= this.db.list('/my/path');//retrieving
  this.db.list('/my/path').push(newItem)//inserting
  </code></pre>