Fragment Caching takes into account localization out of the box

[Santiago Bartesaghi]

Hi everyone,

I'd like to propose an improvement to Rails' fragment caching mechanism. The same way Rails uses a template md5 in the cache key, I propose to automatically add the I18n.locale value to the cache key since it doesn't make sense to ever retrieve a cached entry in another language than the current request.

Let me know if you are interested on it and I can work on the PR :)

Thanks