feat: run the app in Docker Compose with a persistent database

[leouofa]

Runs the web app, background jobs, the Tailwind watcher, and PostgreSQL as a Docker Compose stack, with the database surviving restarts and container recreates.

docker compose up -d --build
docker compose logs -f web

The app comes up on http://localhost:3000, and the first boot prints the seeded admin login. See docs/DOCKER.md.

Persistence

The database lives in the named volume macronx_pg_data, mounted at /var/lib/postgresql and not the older /var/lib/postgresql/data: Postgres 18 sets PGDATA to /var/lib/postgresql/18/docker, so mounting the old path leaves the data in the container layer where it is silently lost on every recreate. Only docker compose down -v destroys it. Uploaded files persist through the working tree bind mount.

Changes

• Dockerfile.dev (new) — development image with the full bundle, plus ffmpeg for the audio pipeline and ImageMagick with libheif for Image::ConvertHeicToJpegJob, which mini_magick needs for its convert binary. Leaves RAILS_ENV unset on purpose: baking in development would defeat ENV['RAILS_ENV'] ||= 'test' in spec/rails_helper.rb and run the suite against macron_x_development.
• compose.yaml (new) — db, web, jobs, and css services. web sets BINDING=0.0.0.0 because Rails binds to localhost in development, which is unreachable from outside a container. jobs waits on the web health check so the two never race to create the same database.
• config/database.yml — reads PGHOST/PGPORT/PGUSER/PGPASSWORD, all unset by default, so local development keeps using the unix socket. Plain PG* variables are not sufficient on their own: Rails always passes a nil host, and libpq then ignores PGHOST. *_DATABASE_URL was avoided deliberately, since it also overrides the test database.
• db/seeds.rb — SEED_ADMIN_EMAIL and SEED_ADMIN_PASSWORD now work in every environment, so a container can be given a known login. Still idempotent.
• Docs — docs/DOCKER.md, linked from the README and SETUP.md, which now reflects the seed variables.

Also in this branch: tags:renumber_id

Unrelated to Docker, but pushed to this branch rather than a PR of its own: a rake task for changing a tag's id.

bin/rails tags:renumber_id OLD_ID=9 NEW_ID=14
# Tag 'reddit' is now id 14.
#   inboxes.tag_id: 1 row(s) remapped.
#   workflows.tag_id: 1 row(s) remapped.

update_column(:id, ...) on its own cannot work: inboxes and workflows both hold foreign keys to tags.id, so the children cannot point at the new id before it exists, and the parent cannot move while children still point at the old one — Postgres raises ForeignKeyViolation either way. Tags::RenumberId reads the referencing constraints out of pg_constraint rather than hardcoding a table list, then drops them, remaps the rows, moves the primary key, and restores them inside one transaction. It runs with requires_new: true so a mid-flight failure rolls back only the remap. Invalid input aborts before touching anything.

docs/MAINTENANCE.md gains a "Changing a tag's id" section covering the arguments, the cases that write nothing, and the foreign key ordering problem. The motivating case is the inbox filter, which carries a tag id in the URL (/inboxes?tag=9), so a bookmarked filter link breaks once the id means a different tag in a restored or migrated database.

Verified

• 270 examples, 0 failures (bundle exec rspec in the container)
• bin/rubocop clean across 129 files
• Data survives docker compose down followed by up; the second boot's db:prepare is a no-op
• Devise sign-in and the dashboard render end to end
• The host's local PostgreSQL is untouched by the containerized suite
• tags:renumber_id run end to end against the test database, plus all five rejected-input paths against development, which write nothing

Note

Unrelated to this change but found while testing: the production Dockerfile installs libvips but not ImageMagick, so Image::ConvertHeicToJpegJob cannot shell out to convert there. Left alone here since the production image is out of scope, but worth a follow-up if IMINT runs in production.