add a release workflow to publish to Github packages (#16)

- update Dockerfile build steps
- add a new github action to deploy pacakge

.github/workflows/release.yml

@@ -0,0 +1,41 @@
+name: Release Package
+
+on:
+  release:
+    types: [published]
+
+env:
+  REGISTRY: ghcr.io
+  IMAGE_NAME: ${{ github.repository }}
+
+jobs:
+  build-and-push-image:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+
+      - name: Log in to the Container registry
+        uses: docker/#-action@v2
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Extract metadata (tags, labels) for Docker
+        id: meta
+        uses: docker/metadata-action@v4
+        with:
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v3
+        with:
+          context: .
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}

Dockerfile

@@ -1,10 +1,21 @@
+# Reference: https://docs.docker.com/language/golang/build-images/
+
+# Start from golang base image
 FROM golang:latest as builder
 
+# Set the Current Working Directory inside the container
 WORKDIR /
-COPY . .
-RUN go get -d -v ./...
-RUN CGO_ENABLED=0 GOOS=linux go build -a -o /go/bin/scout
 
+# Copy module files and download dependencies
+COPY go.mod .
+COPY go.sum .
+RUN go mod download
+
+# Build the Go app
+COPY *.go .
+RUN CGO_ENABLED=0 GOOS=linux go build -a -o /go/bin/scout .
+
+######## Start a new stage from scratch #######
 FROM alpine:latest
 RUN apk --no-cache add ca-certificates tzdata
 COPY --from=builder /go/bin/scout /usr/local/bin