Comment 3 for bug 830309

Pre-implementation discussion:

- ApplicationDemo would be a separate model, with just a ppaid, signing key, package name and a foreign key to Application "is_demo_of".
- Demos will always be free (gratis), and they should only be an option for paid (as in price > 0) apps.
- Apps with a demo shouldn't be allowed to update their price to 0 without deleting the demo first (doesn't sound like many devs would even try to do so, but still).
- Apps should be allowed to have at most one demo version.
- Demos should be a separate package that can be superseded by the full version.
- In the API, the demo can be included inlined within the application, in the available-apps-for-purchase call, as in { 'name': 'Foobar', demo: {'ppa_id': 'foo',...}, 'ppa_id': '...'}, and demo can be null.
- This stub api should be provided as early as possible, so that the client can start handling it.
- For the UI for creating a demo, you will have a "Create a demo for this app" button on paid apps details page, possibly in the calls to action on the right
- The creation workflow could probably be boiled down to a single screen for demos.

Looks like this bug should be split out into multiple bugs next