Inflector rules (singularization and pluralization) for Spanish

Hey, guys. Thought Spanish speakers who follow this board may appreciate
that I’ve added Spanish inflector rules in my inflections gem:

I’m fairly well versed in Spanish, but I’m not a native speaker. If
notices errors or missing rules, please submit a pull request and help

Likewise, if you speak another language, it’d be awesome to get some
inflection lists into the gem for other foreign languages.