TM.Users = DS.Model.extend({
    job_number: DS.attr(),
    purl: DS.attr(),
    record_type: DS.attr(),
    sessions: DS.attr()
});

TM.Users.FIXTURES = [
    {
        "id": "1",
        "job_number": "1234",
        "purl": "1234jdoe",
        "details": {
            "forename": "John",
            "surname": "Doe",
        },
        "sessions": [{
            "browser_name": "chrome",
            "browser_version": "33.0.1750.112",
            "os_name": "macintosh",
            "os_version": "os x",
        }]
}];

<!-- code from my handlbars file -->
  <script type="text/x-handlebars" id="view">
    <p>Browser Name</p>
    <p>{{sessions.browser_name}}</p>
  </script>