Add CI, releases, and version flag

- Add GitHub Actions CI workflow (test, lint, build matrix)
- Add GitHub Actions release workflow with GoReleaser
- Add .goreleaser.yml for multi-platform binary releases
- Add -v/--version flag with build info
- Add godoc comments to codes package
- Update README with CI badge and release instructions

Author: cv

.github/workflows/ci.yml

@@ -0,0 +1,70 @@
+name: CI
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+    branches: [master]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Go
+        uses: actions/setup-go@v5
+        with:
+          go-version-file: go.mod
+
+      - name: Download dependencies
+        run: go mod download
+
+      - name: Run tests
+        run: go test -v -race -coverprofile=coverage.out ./...
+
+      - name: Upload coverage
+        uses: codecov/codecov-action@v4
+        with:
+          files: coverage.out
+        continue-on-error: true
+
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Go
+        uses: actions/setup-go@v5
+        with:
+          go-version-file: go.mod
+
+      - name: Run golangci-lint
+        uses: golangci/golangci-lint-action@v6
+        with:
+          version: latest
+
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        goos: [linux, darwin, windows]
+        goarch: [amd64, arm64]
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Go
+        uses: actions/setup-go@v5
+        with:
+          go-version-file: go.mod
+
+      - name: Build
+        env:
+          GOOS: ${{ matrix.goos }}
+          GOARCH: ${{ matrix.goarch }}
+        run: |
+          binary_name="t"
+          if [ "$GOOS" = "windows" ]; then
+            binary_name="t.exe"
+          fi
+          go build -o "${binary_name}" ./cmd/t

.github/workflows/release.yml

@@ -0,0 +1,30 @@
+name: Release
+
+on:
+  push:
+    tags:
+      - 'v*'
+
+permissions:
+  contents: write
+
+jobs:
+  release:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Set up Go
+        uses: actions/setup-go@v5
+        with:
+          go-version-file: go.mod
+
+      - name: Run GoReleaser
+        uses: goreleaser/goreleaser-action@v6
+        with:
+          version: latest
+          args: release --clean
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.goreleaser.yml

@@ -0,0 +1,44 @@
+version: 2
+
+project_name: t
+
+before:
+  hooks:
+    - go mod tidy
+
+builds:
+  - main: ./cmd/t
+    binary: t
+    env:
+      - CGO_ENABLED=0
+    goos:
+      - linux
+      - darwin
+      - windows
+    goarch:
+      - amd64
+      - arm64
+    ldflags:
+      - -s -w
+      - -X main.version={{.Version}}
+      - -X main.commit={{.ShortCommit}}
+      - -X main.date={{.Date}}
+
+archives:
+  - format: tar.gz
+    name_template: >-
+      {{ .ProjectName }}_{{ .Version }}_{{ .Os }}_{{ .Arch }}
+    format_overrides:
+      - goos: windows
+        format: zip
+
+checksum:
+  name_template: 'checksums.txt'
+
+changelog:
+  sort: asc
+  filters:
+    exclude:
+      - '^docs:'
+      - '^test:'
+      - '^ci:'

README.md

@@ -1,13 +1,21 @@
 # t
 
+[![CI](https://github.com/cv/t/actions/workflows/ci.yml/badge.svg)](https://github.com/cv/t/actions/workflows/ci.yml)
+
 A quick and simple world clock for the command-line using IATA airport codes.
 
 ## Installation
 
+### From source
+
 ```bash
 go install github.com/cv/t/cmd/t@latest
 ```
 
+### From releases
+
+Download the latest binary from the [releases page](https://github.com/cv/t/releases).
+
 ## Usage
 
 ```bash
@@ -18,6 +26,13 @@ JFK: 🕖  19:06:21 (America/New_York)
 
 Any IATA airport code can be used, and will pick the timezone of that airport.
 
+### Version
+
+```bash
+$ t --version
+t v1.0.0 (commit: abc1234, built: 2024-01-01T00:00:00Z)
+```
+
 ### Shell Prompt Mode
 
 If `PS1_FORMAT` is set, the output will be compact with no decorations or newline, suitable for shell prompts:
@@ -43,40 +58,45 @@ go build -o t ./cmd/t
 
 ```bash
 # Run all tests
-go test ./...
+make test
 
 # Run with coverage
-go test -cover ./...
+make test-cover
 
 # Run with race detector
-go test -race ./...
-
-# Generate coverage report
-go test -coverprofile=coverage.out ./...
-go tool cover -html=coverage.out -o coverage.html
+make test-race
 ```
 
 ### Linting
 
 ```bash
-# Install golangci-lint
-go install github.com/golangci/golangci-lint/cmd/golangci-lint@latest
+make lint
+```
 
-# Run linters
-golangci-lint run
+### Releasing
+
+Releases are automated via GitHub Actions. To create a new release:
+
+```bash
+git tag v1.0.0
+git push origin v1.0.0
 ```
 
 ## Project Structure
 
 ```
 t/
+├── .github/workflows/  # CI and release automation
+│   ├── ci.yml
+│   └── release.yml
 ├── cmd/t/              # Main application entry point
 │   └── main.go
 ├── codes/              # IATA airport code to timezone mapping
 │   └── iata.go
 ├── internal/clock/     # Core clock display logic
 │   ├── clock.go
 │   └── clock_test.go
+├── .goreleaser.yml     # Release configuration
 ├── go.mod
 ├── go.sum
 └── README.md

cmd/t/main.go

@@ -3,6 +3,7 @@
 // Usage:
 //
 //	t <IATA>...
+//	t -v | --version
 //
 // Examples:
 //
@@ -22,12 +23,25 @@ import (
 	"github.com/cv/t/internal/clock"
 )
 
+// Version information set by goreleaser ldflags
+var (
+	version = "dev"
+	commit  = "none"
+	date    = "unknown"
+)
+
 func main() {
 	if len(os.Args) < 2 {
 		fmt.Fprint(os.Stderr, "usage: t <IATA>...\n")
 		os.Exit(1)
 	}
 
+	// Handle version flag
+	if os.Args[1] == "-v" || os.Args[1] == "--version" {
+		fmt.Printf("t %s (commit: %s, built: %s)\n", version, commit, date)
+		return
+	}
+
 	ps1Format := os.Getenv("PS1_FORMAT") != ""
 	clock.ShowAll(os.Stdout, os.Args[1:], ps1Format, nil)
 }

codes/iata.go

@@ -1,5 +1,8 @@
+// Package codes provides IATA airport code to timezone mappings.
 package codes
 
+// IATA maps airport codes to their corresponding IANA timezone identifiers.
+// For example, "SFO" maps to "America/Los_Angeles".
 var IATA = map[string]string{
 	"3BB": "America/Detroit",
 	"AAA": "Pacific/Tahiti",