Add example htaccess file with rewrite rules.
Add code to create new artists.

Add the routes and views to support the creation of new artist
records:

* Set guarded fields for Artist model.
* Add condition for /artists/:id route (to avoid conflict
    with /artists/create and /artists/save routes used to
    create new artists).
* Add /artists/create route for displaying form to create new
    artists.
* Add /artists/save route for saving artists.
* Move artist views into views/artists/ subdirectory.
* Add create and _form vies for artists.

TODO: add edit and image upload code.