通过更改ActionController::Base#page_cache_directory, Heroku上的静态资产缓存

I'm attempting to use Jammit for packaging CSS and JS for a Rails app deployed on Heroku, which doesn't work out of the box due to Heroku's read only file system. Every example I've seen of how to do this recommends building all the packaged asset files in advance. Because of Heroku's Git-based deployment, this means you need to make a separate commit to your repository every time these files change, which is not an acceptable solution to me. Instead, I want to change the path that Jammit uses to write the cached packages to I'm attempting to use Jammit for packaging CSS