Add docker file

Dockerfile

@@ -0,0 +1,27 @@
+# syntax=docker/dockerfile:1
+FROM golang:1.21 AS build-stage
+WORKDIR /app
+
+COPY go.mod ./
+RUN go mod download
+
+COPY *.go ./
+COPY ./templates/ ./templates/
+COPY ./well-known/ ./well-known/
+COPY ./static/ ./static/
+COPY humans.txt ./
+COPY robots.txt ./
+
+RUN CGO_ENABLED=0 GOOS=linux go build -o /mstar
+
+FROM gcr.io/distroless/base-debian11 AS build-release-stage
+
+WORKDIR /
+
+COPY --from=build-stage /mstar /mstar
+
+EXPOSE 8080
+
+USER nonroot:nonroot
+
+ENTRYPOINT [ "/mstar" ]