add dockerfile for backend && update docker-compose.yml

backend/Dockerfile

@@ -0,0 +1,34 @@
+# Stage 1: Builder
+FROM golang:1.25-alpine AS builder
+
+WORKDIR /app
+
+# Install git and build dependencies
+RUN apk add --no-cache git
+
+# Copy go mod files
+COPY go.mod go.sum ./
+RUN go mod download
+
+# Copy source code
+COPY . .
+
+# Build the application
+RUN CGO_ENABLED=0 GOOS=linux go build -o api ./cmd/api
+
+# Stage 2: Production
+FROM alpine:latest AS production
+
+RUN apk --no-cache add ca-certificates
+
+WORKDIR /app
+
+# Copy binary from builder
+COPY --from=builder /app/api .
+
+# Copy migrations
+COPY internal/db/migrations ./migrations
+
+EXPOSE 8080
+
+CMD ["./api"]

docker-compose.yml

@@ -1,4 +1,36 @@
 services:
+  # PostgreSQL database
+  postgres:
+    image: postgres:16-alpine
+    environment:
+      POSTGRES_USER: egor
+      POSTGRES_PASSWORD: barsik
+      POSTGRES_DB: delivery_tracker
+    volumes:
+      - postgres_data:/var/lib/postgresql/data
+    ports:
+      - "5432:5432"
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U egor -d delivery_tracker"]
+      interval: 5s
+      timeout: 5s
+      retries: 5
+
+  # Backend API
+  backend:
+    build:
+      context: ./backend
+      dockerfile: Dockerfile
+      target: production
+    environment:
+      DATABASE_URL: postgres://egor:barsik@postgres:5432/delivery_tracker?sslmode=disable
+    ports:
+      - "8081:8080"
+    depends_on:
+      postgres:
+        condition: service_healthy
+    restart: unless-stopped
+
   # Development service with hot reload
   frontend-dev:
     image: node:20-alpine
@@ -22,7 +54,10 @@ services:
       target: production
     ports:
       - "8080:80"
+    depends_on:
+      - backend
     restart: unless-stopped
 
 volumes:
   node_modules:
+  postgres_data: