How we organize and get things done with SERVICEOWNERS

This post introduces SERVICEOWNERS as a new layer of abstraction for organizing engineers and code around services within GitHub's large Ruby on Rails monolith. It details the `SERVICEOWNERS` file, `service-mappings.yaml`, the `serviceowners` Ruby gem, and the `ownership.yaml` file. The system aims to provide consistent, company-wide grouping of functionality to humans, leading to a shared lexicon, reduced disruption from team reorganizations, and a centralized service catalog. The service catalog visualizes service relationships, dependencies, and information about maintainers and SLAs, which aids in onboarding and incident remediation. The gem generates the `CODEOWNERS` file dynamically and provides a chat-op for querying service ownership.