feat: Add Docker support for easy distribution

- Multi-stage Dockerfile for minimal image size (~119MB)
- Includes PostgreSQL, MySQL, MariaDB client tools
- Non-root user (UID 1000) for security
- Docker Compose examples for all use cases
- Complete Docker documentation (DOCKER.md)
- Kubernetes CronJob examples
- Support for Docker secrets
- Multi-platform build support

Docker makes deployment trivial:
- No dependency installation needed
- Consistent environment
- Easy CI/CD integration
- Kubernetes-ready

.dockerignore

@@ -0,0 +1,21 @@
+.git
+.gitignore
+*.dump
+*.dump.gz
+*.sql
+*.sql.gz
+*.tar.gz
+*.sha256
+*.info
+.dbbackup.conf
+backups/
+test_workspace/
+bin/
+dbbackup
+dbbackup_*
+*.log
+.vscode/
+.idea/
+*.swp
+*.swo
+*~

DOCKER.md

@@ -0,0 +1,250 @@
+# Docker Usage Guide
+
+## Quick Start
+
+### Build Image
+
+```bash
+docker build -t dbbackup:latest .
+```
+
+### Run Container
+
+**PostgreSQL Backup:**
+```bash
+docker run --rm \
+  -v $(pwd)/backups:/backups \
+  -e PGHOST=your-postgres-host \
+  -e PGUSER=postgres \
+  -e PGPASSWORD=secret \
+  dbbackup:latest backup single mydb
+```
+
+**MySQL Backup:**
+```bash
+docker run --rm \
+  -v $(pwd)/backups:/backups \
+  -e MYSQL_HOST=your-mysql-host \
+  -e MYSQL_USER=root \
+  -e MYSQL_PWD=secret \
+  dbbackup:latest backup single mydb --db-type mysql
+```
+
+**Interactive Mode:**
+```bash
+docker run --rm -it \
+  -v $(pwd)/backups:/backups \
+  -e PGHOST=your-postgres-host \
+  -e PGUSER=postgres \
+  -e PGPASSWORD=secret \
+  dbbackup:latest interactive
+```
+
+## Docker Compose
+
+### Start Test Environment
+
+```bash
+# Start test databases
+docker-compose up -d postgres mysql
+
+# Wait for databases to be ready
+sleep 10
+
+# Run backup
+docker-compose run --rm postgres-backup
+```
+
+### Interactive Mode
+
+```bash
+docker-compose run --rm dbbackup-interactive
+```
+
+### Scheduled Backups with Cron
+
+Create `docker-cron`:
+```bash
+#!/bin/bash
+# Daily PostgreSQL backup at 2 AM
+0 2 * * * docker run --rm -v /backups:/backups -e PGHOST=postgres -e PGUSER=postgres -e PGPASSWORD=secret dbbackup:latest backup single production_db
+```
+
+## Environment Variables
+
+**PostgreSQL:**
+- `PGHOST` - Database host
+- `PGPORT` - Database port (default: 5432)
+- `PGUSER` - Database user
+- `PGPASSWORD` - Database password
+- `PGDATABASE` - Database name
+
+**MySQL/MariaDB:**
+- `MYSQL_HOST` - Database host
+- `MYSQL_PORT` - Database port (default: 3306)
+- `MYSQL_USER` - Database user
+- `MYSQL_PWD` - Database password
+- `MYSQL_DATABASE` - Database name
+
+**General:**
+- `BACKUP_DIR` - Backup directory (default: /backups)
+- `COMPRESS_LEVEL` - Compression level 0-9 (default: 6)
+
+## Volume Mounts
+
+```bash
+docker run --rm \
+  -v /host/backups:/backups \              # Backup storage
+  -v /host/config/.dbbackup.conf:/home/dbbackup/.dbbackup.conf:ro \  # Config file
+  dbbackup:latest backup single mydb
+```
+
+## Docker Hub
+
+Pull pre-built image (when published):
+```bash
+docker pull uuxo/dbbackup:latest
+docker pull uuxo/dbbackup:1.0
+```
+
+## Kubernetes Deployment
+
+**CronJob Example:**
+```yaml
+apiVersion: batch/v1
+kind: CronJob
+metadata:
+  name: postgres-backup
+spec:
+  schedule: "0 2 * * *"  # Daily at 2 AM
+  jobTemplate:
+    spec:
+      template:
+        spec:
+          containers:
+          - name: dbbackup
+            image: dbbackup:latest
+            args: ["backup", "single", "production_db"]
+            env:
+            - name: PGHOST
+              value: "postgres.default.svc.cluster.local"
+            - name: PGUSER
+              value: "postgres"
+            - name: PGPASSWORD
+              valueFrom:
+                secretKeyRef:
+                  name: postgres-secret
+                  key: password
+            volumeMounts:
+            - name: backups
+              mountPath: /backups
+          volumes:
+          - name: backups
+            persistentVolumeClaim:
+              claimName: backup-storage
+          restartPolicy: OnFailure
+```
+
+## Docker Secrets
+
+**Using Docker Secrets:**
+```bash
+# Create secrets
+echo "mypassword" | docker secret create db_password -
+
+# Use in stack
+docker stack deploy -c docker-stack.yml dbbackup
+```
+
+**docker-stack.yml:**
+```yaml
+version: '3.8'
+services:
+  backup:
+    image: dbbackup:latest
+    secrets:
+      - db_password
+    environment:
+      - PGHOST=postgres
+      - PGUSER=postgres
+      - PGPASSWORD_FILE=/run/secrets/db_password
+    command: backup single mydb
+    volumes:
+      - backups:/backups
+
+secrets:
+  db_password:
+    external: true
+
+volumes:
+  backups:
+```
+
+## Image Size
+
+**Multi-stage build results:**
+- Builder stage: ~500MB (Go + dependencies)
+- Final image: ~100MB (Alpine + clients)
+- Binary only: ~15MB
+
+## Security
+
+**Non-root user:**
+- Runs as UID 1000 (dbbackup user)
+- No privileged operations needed
+- Read-only config mount recommended
+
+**Network:**
+```bash
+# Use custom network
+docker network create dbnet
+
+docker run --rm \
+  --network dbnet \
+  -v $(pwd)/backups:/backups \
+  dbbackup:latest backup single mydb
+```
+
+## Troubleshooting
+
+**Check logs:**
+```bash
+docker logs dbbackup-postgres
+```
+
+**Debug mode:**
+```bash
+docker run --rm -it \
+  -v $(pwd)/backups:/backups \
+  dbbackup:latest backup single mydb --debug
+```
+
+**Shell access:**
+```bash
+docker run --rm -it --entrypoint /bin/sh dbbackup:latest
+```
+
+## Building for Multiple Platforms
+
+```bash
+# Enable buildx
+docker buildx create --use
+
+# Build multi-arch
+docker buildx build \
+  --platform linux/amd64,linux/arm64,linux/arm/v7 \
+  -t uuxo/dbbackup:latest \
+  --push .
+```
+
+## Registry Push
+
+```bash
+# Tag for registry
+docker tag dbbackup:latest git.uuxo.net/uuxo/dbbackup:latest
+docker tag dbbackup:latest git.uuxo.net/uuxo/dbbackup:1.0
+
+# Push to private registry
+docker push git.uuxo.net/uuxo/dbbackup:latest
+docker push git.uuxo.net/uuxo/dbbackup:1.0
+```

Dockerfile

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+# Multi-stage build for minimal image size
+FROM golang:1.24-alpine AS builder
+
+# Install build dependencies
+RUN apk add --no-cache git make
+
+WORKDIR /build
+
+# Copy go mod files
+COPY go.mod go.sum ./
+RUN go mod download
+
+# Copy source code
+COPY . .
+
+# Build binary
+RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -ldflags="-w -s" -o dbbackup .
+
+# Final stage - minimal runtime image
+FROM alpine:3.19
+
+# Install database client tools
+RUN apk add --no-cache \
+    postgresql-client \
+    mysql-client \
+    mariadb-client \
+    pigz \
+    pv \
+    ca-certificates \
+    tzdata
+
+# Create non-root user
+RUN addgroup -g 1000 dbbackup && \
+    adduser -D -u 1000 -G dbbackup dbbackup
+
+# Copy binary from builder
+COPY --from=builder /build/dbbackup /usr/local/bin/dbbackup
+RUN chmod +x /usr/local/bin/dbbackup
+
+# Create backup directory
+RUN mkdir -p /backups && chown dbbackup:dbbackup /backups
+
+# Set working directory
+WORKDIR /backups
+
+# Switch to non-root user
+USER dbbackup
+
+# Set entrypoint
+ENTRYPOINT ["/usr/local/bin/dbbackup"]
+
+# Default command shows help
+CMD ["--help"]
+
+# Labels
+LABEL maintainer="UUXO"
+LABEL version="1.0"
+LABEL description="Professional database backup tool for PostgreSQL, MySQL, and MariaDB"

README.md

@@ -16,6 +16,31 @@ Professional database backup and restore utility for PostgreSQL, MySQL, and Mari
 
 ## Installation
 
+### Docker (Recommended)
+
+**Pull from registry:**
+```bash
+docker pull git.uuxo.net/uuxo/dbbackup:latest
+```
+
+**Quick start:**
+```bash
+# PostgreSQL backup
+docker run --rm \
+  -v $(pwd)/backups:/backups \
+  -e PGHOST=your-host \
+  -e PGUSER=postgres \
+  -e PGPASSWORD=secret \
+  git.uuxo.net/uuxo/dbbackup:latest backup single mydb
+
+# Interactive mode
+docker run --rm -it \
+  -v $(pwd)/backups:/backups \
+  git.uuxo.net/uuxo/dbbackup:latest interactive
+```
+
+See [DOCKER.md](DOCKER.md) for complete Docker documentation.
+
 ### Download Pre-compiled Binary
 
 Linux x86_64:

docker-compose.yml

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+version: '3.8'
+
+services:
+  # PostgreSQL backup example
+  postgres-backup:
+    build: .
+    image: dbbackup:latest
+    container_name: dbbackup-postgres
+    volumes:
+      - ./backups:/backups
+      - ./config/.dbbackup.conf:/home/dbbackup/.dbbackup.conf:ro
+    environment:
+      - PGHOST=postgres
+      - PGPORT=5432
+      - PGUSER=postgres
+      - PGPASSWORD=secret
+    command: backup single mydb
+    depends_on:
+      - postgres
+    networks:
+      - dbnet
+
+  # MySQL backup example
+  mysql-backup:
+    build: .
+    image: dbbackup:latest
+    container_name: dbbackup-mysql
+    volumes:
+      - ./backups:/backups
+    environment:
+      - MYSQL_HOST=mysql
+      - MYSQL_PORT=3306
+      - MYSQL_USER=root
+      - MYSQL_PWD=secret
+    command: backup single mydb --db-type mysql
+    depends_on:
+      - mysql
+    networks:
+      - dbnet
+
+  # Interactive mode example
+  dbbackup-interactive:
+    build: .
+    image: dbbackup:latest
+    container_name: dbbackup-tui
+    volumes:
+      - ./backups:/backups
+    environment:
+      - PGHOST=postgres
+      - PGUSER=postgres
+      - PGPASSWORD=secret
+    command: interactive
+    stdin_open: true
+    tty: true
+    networks:
+      - dbnet
+
+  # Test PostgreSQL database
+  postgres:
+    image: postgres:15-alpine
+    container_name: test-postgres
+    environment:
+      - POSTGRES_PASSWORD=secret
+      - POSTGRES_DB=mydb
+    volumes:
+      - postgres-data:/var/lib/postgresql/data
+    networks:
+      - dbnet
+
+  # Test MySQL database
+  mysql:
+    image: mysql:8.0
+    container_name: test-mysql
+    environment:
+      - MYSQL_ROOT_PASSWORD=secret
+      - MYSQL_DATABASE=mydb
+    volumes:
+      - mysql-data:/var/lib/mysql
+    networks:
+      - dbnet
+
+volumes:
+  postgres-data:
+  mysql-data:
+
+networks:
+  dbnet:
+    driver: bridge