added Docker build and auth_service.config.dev

Dockerfile

@@ -0,0 +1,17 @@
+FROM golang:1.24.3 AS build-stage
+
+WORKDIR /app
+
+COPY . .
+
+RUN go build
+
+FROM gcr.io/distroless/base-debian12 AS build-release-stage
+
+WORKDIR /data
+
+COPY --from=build-stage /app/auth_service /auth_service
+COPY users.json /data/users.json
+COPY auth_service.config /data/auth_service.config
+
+ENTRYPOINT [ "/auth_service" ]