Improve how to deal with multiple metadata fields

[cavalle]

Currently this is the only way you can set metadata fields of type multiple using Almodovar:

title.metadata.update :metadata => { :genres => [ {:genre => "Drama"}, {:genre => "Thriller"}] }

that generates the following XML…

<metadata>
  <genres type="array">
    <genre>
      <genre>Drama</genre>
    </genre>
    <genre>
      <genre>Thriller</genre>
    </genre>
  </genres>
</metadata>

…which is not the right XML but still it seems to work thanks to some ActiveSupport's black magic in the side of the server.

Ugly.

What Almodovar should support is this:

title.metadata.update :metadata => { :genres => ["Drama", "Thriller"] }

…which would generate this:

<metadata>
  <genres type="array">
    <genre>Drama</genre>
    <genre>Thriller</genre>
  </genres>
</metadata>