Posting an Interest

> A user is interested in hybrid mobile apps and submits “Advantages and Disadvantages of hybrid apps” as an interest to a Barcamp event about app development. They will decided whether to attend based on the feedback.

It is already possible to submit an Interest. What's missing:

* [ ] On the starting page load/show the rest of the form instead of forwarding to `/interset` with an error directly
* [ ] make the `/interest/` and `/interest/:id` routes beautiful => proper markup/layout