Flask snippet 35: http://flask.pocoo.org/snippets/35/

URL proxy.

Was a Typo: 'ContentType'.

into experiment index.html on install.

Previous solution of appending the template script after the html tag
was unreliable.

SCRIPT_ROOT is necessary for posting to experiment factory deployed
behind a reverse proxy. Experiment must POST to SCRIPT_ROOT + '/save'.

```js
on_finish: function(data) {
  // Get the data.
  var data = jsPsych.data.get();

  var request = $.post(
    SCRIPT_ROOT + '/save',
    {'data': data.json()},
    function() {
      // Success, go to /next.
      document.location = SCRIPT_ROOT + '/next';
    },
    'json')
      .fail(function() {
        // Error, local save.
        data.localSave('json', 'results.json');
        document.location = SCRIPT_ROOT + '/next';
      });
}
```