If you are using docker for your rails deploys you might have run into the issue of compiling your assets before you database container is available. The usual solution is to precompile the assets on your local machine and track them within you version control system. There is, however, an alternative: use a fake DB adapter during asset compilation.

http://blog.zeit.io/use-a-fake-db-adapter-to-play-nice-with-rails-assets-precompilation/