Cucumber + CI features for ActiveRecord

[bolshakov]

Background

Stoplight guarantees that all data stores behave identically. The cucumber feature suite encodes that guarantee: the same scenarios run against each backend, chosen by the STOPLIGHT_DATA_STORE environment variable, so a new backend must pass the same behavioral suite as Redis and Memory. This ticket adds the ActiveRecord run to that suite and to CI.

Goal

Run the cucumber feature suite against the ActiveRecord backend, extending the backend-parity gate to cover it.

What to do

• Add an ActiveRecord branch to the cucumber data-store selection, driven by STOPLIGHT_DATABASE_URL (SQLite default), with its own cleaner.
• Run the ActiveRecord cucumber suite on SQLite in the CI features job.
• Update the contributor testing docs to list the new STOPLIGHT_DATA_STORE value.

Acceptance criteria

• STOPLIGHT_DATA_STORE=ActiveRecord bundle exec cucumber passes locally on SQLite with no services running.
• The CI features job runs the ActiveRecord suite (SQLite) alongside the existing backends and is green.
• The contributor testing docs list the ActiveRecord data-store value.

References

• Feature suite: features/
• Store selection: features/stoplight/support/stoplight_world.rb
• CI: .github/workflows/ci.yml
• Testing guide: docs/testing.md