Use Current API

[virolea]

The initial implementation of the locale per thread was done manually by setting Thread.current[:rosetta_locale_session] to an instance of Rosetta::LocaleSession.

This model encapsulates the logic of finding the correct locale based on the supplied input and fallback to the default locale if not found. This works well but I wondered if we'd be better off simply using the Rails CurrentAtributes API.

• It's reset after each request, removing the need for Rosetta#with_locale to ensure the locale is set back to whatever it was before
• It's built-in rails
• One less thread-related consideration in the code, this simplifies things.

Warning

CurrentAttributes being a thread level singleton instance, one needs to be careful not to override any potential user-defined attribute.