Slow performance on boot with many translations

[listrophy]

We added lit to a Spree project, and now it takes significantly longer to boot up the server.

A quick benchmark (on my dev machine) yielded:

• ~5.5sec with config/initializers/lit.rb commented out
• ~12.5sec with config/initializers/lit.rb intact

By using Spree, we automatically get ~1500 keys out of the box, multiplied by about 20 locales. As a first attempt at improving speeds, we've removed all but the en-US locales (which is all we need right now). That improved the bad number to about 9.5sec. Better, but still not great.

I'm willing to help out making improvements, but I'd like some guidance first. Any thoughts?