Artworks and Galleries

Don't merge. Todo: tests.
Hah, give it a shot @ardation. The `page` method is pretty nifty and just adds `LIMIT` and `OFFSET` clauses to the query so you can keep on chaining whatever you like onto it.

I had to double check that I wasn't crazy, here's the result in the console:

```ruby
Artwork.page(1).recent.to_sql
=> "SELECT  \"artworks\".* FROM \"artworks\"  WHERE (created_at between '2014-10-29 00:00:00.000000' and '2014-10-29 23:59:59.999999') LIMIT 12 OFFSET 0"
```