If you ever had to make existing (Slim) templates localizable for the
internationalization of your Rails app, you know it is a real pain and
takes ages!
We have built a neat tool to extract all localizable strings from Slim
templates and to replace them with generated keys for the Rails i18n
module: Slimkeyfy
See the project on our Github page: GitHub - phrase/slimkeyfy: Extract plain Strings from .slim views and rails controllers to replace them with I18n's t() method
We have also put together a blog post that explains in detail how it
works:
We hope we can save you hours of boring work, just like the tool saved
ourselves days of template localization 
Best,
Manuel