add dockerfile for distroless image

Dockerfile

@@ -0,0 +1,15 @@
+FROM golang:1.22-bookworm as golang
+WORKDIR /app
+
+RUN apt-get update && apt-get install -y apt-file libwebp-dev
+
+COPY ["go.mod", "go.sum", "./"]
+RUN go mod download && go mod verify
+
+COPY ./ ./
+RUN CGO_ENABLED=1 go build -o app ./
+
+FROM gcr.io/distroless/base-debian12
+COPY --from=golang /usr/lib/*/libwebp*.so* /usr/lib/
+COPY --from=golang /app/app /achievement-bot
+CMD ["/achievement-bot"]