Change from routing using get/post to resource routing.

- Show rake routes before
- Show rake routes after – it's the same!
Add links to index page and new page.

- Start by using <a>
- Then use link_to with URL
- Finally use link_to with named path.

- Why?
  http://stackoverflow.com/questions/3951582/why-does-rails-use-helper-methods-like-link-to-instead-of-a-href