capistrano-multiyaml

https://github.com/agperson/capistrano-multiyaml

This plugin simplifies and clarifies the multistage deploy process by reading settings from a simple YAML file that can be updated programatically. Even if the file is only managed by humans, there are still several benefits including centralizing stage/role configuration in one file, discouraging per-stage logic in deference to properly hooked before/after callbacks, and simplified configuration reuse.