Add Rubocop

[schoblaska]

• Grab a .rubocop.yml file from an existing @rubyatscale repo
• Fix violations
• Add a step to the CI workflow that runs Rubocop

This repo embeds two Rails apps for testing. The Rubocop rules can ignore those directories.

[github-actions]

This issue has been marked stale because it has been open for six months with no activity. To prevent this issue from automatically being closed in one week, update it or remove the stale label.

[tstannard]

Commenting to keep this open