or a site that lets users list their properties to rent. At any given time, we should be able to answer questions about the current state like <em>What rental are they looking at?</em> and <em>Are they editing it?</em> In Ember, the answer to these questions is determined by the URL.
The URL can be set in a few ways:</p>
<ul>
<li>The user loads the app for the first time.</li>
<li>The user changes the URL manually, such as by clicking the back button or by editing the address bar.</li>
<li>The user clicks a