dhh-rails-style

<objective>
Apply 37signals/DHH Rails conventions to Ruby and Rails code. This skill provides comprehensive domain expertise extracted from analyzing production 37signals codebases (Fizzy/Campfire) and DHH's code review patterns.
</objective>

<essential_principles>
## Core Philosophy

"The best code is the code you don't write. The second best is the code that's obviously correct."

**Vanilla Rails is plenty:**
- Rich domain models over service objects
- CRUD controllers over custom actions
- Concerns for horizontal code sharing
- Records as state instead of boolean columns
- Database-backed everything (no Redis)
- Build solutions before reaching for gems

**What they deliberately avoid:**
- devise (custom ~150-line auth instead)
- pundit/cancancan (simple role checks in models)
- sidekiq (Solid Queue uses database)
- redis (database for everything)
- view_component (partials work fine)
- GraphQL (REST with Turbo sufficient)
- factory_bot (fixtures are simpler)
- rspec (Minitest ships with Rails)
- Tailwind (native CSS with layers)

**Development Philosophy:**
- Ship, Validate, Refine - prototype-quality code to production to learn
- Fix root causes, not symptoms
- Write-time operations over read-time computations
- Database constraints over ActiveRecord validations
</essential_principles>

<intake>
What are you working on?

1. **Controllers** - REST mapping, concerns, Turbo responses, API patterns
2. **Models** - Concerns, state records, callbacks, scopes, POROs
3. **Views & Frontend** - Turbo, Stimulus, CSS, partials
4. **Architecture** - Routing, multi-tenancy, authentication, jobs, caching
5. **Testing** - Minitest, fixtures, integration tests
6. **Gems & Dependencies** - What to use vs avoid
7. **Code Review** - Review code against DHH style
8. **General Guidance** - Philosophy and conventions

**Specify a number or describe your task.**
</intake>

<routing>

| Response | Reference to Read |
|----------|-------------------|
| 1, controller | [controllers.md](.