Add new Rails/CalendarTypeSuffix cop

[jmks]

Adds a new cop that checks for column names to match a convention for calendar types (time, date, and datetime).
Inspired from here, specifically:

• Name date columns with _on suffixes.
• Name datetime columns with _at suffixes.
• Name time columns (referring to a time of day with no date) with _time suffixes.

These suffixes are configurable.

I have a question: The db/schema.rb is excluded by default on all Cops. AFAIK, there's no way to override that on a per-cop basis? I tried the Include option but it does not show up in --list-target-files.

For testing, I can force it to run agains the file with bundle exec rubocop db/schema.rb --only Rails/CalendarTypeSuffix.

Maybe this makes the cop a no-go?

---

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• Wrote good commit messages.
• Commit message starts with [Fix #issue-number] (if the related issue exists).
• Feature branch is up-to-date with master (if not - rebase it).
• Squashed related commits together.
• Added tests.
• Added an entry to the Changelog if the new code introduces user-observable changes. See changelog entry format.
• The PR relates to only one subject with a clear title
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• Run bundle exec rake default. It executes all tests and RuboCop for itself, and generates the documentation.
• If this is a new cop, consider making a corresponding update to the Rails Style Guide.

[andyw8]

This seem very similar to #335 ?

[jmks]

Ah, I ported this from some internal cop I had.

#335 scans the db/migrations which I guess avoids the issue with violations against db/schema.rb. But it also would not have a "backlog" of violations to fix (migrations tend to not stay around forever).

I think that one would work well enough. I can close this.