Use ruby-style URLs

URLs now follow the following format:
http://foo.com/reforma/:tag_slug/ley/:law_slug/articulo/:article_number

Slugs, laws, and articles support CRUD.
To edit something, just append */edit* to the end of the URL.
To create something, just do:
- /law/create
- /tag/create
- /article/create

The "destroy" action is not currently supported.