feat: add docker configuration

rate/Dockerfile

@@ -0,0 +1,16 @@
+FROM docker.io/golang:latest AS builder
+WORKDIR /build
+EXPOSE 5003
+
+COPY . ./
+RUN go mod download -x
+ENV CGO_ENABLED 0
+RUN go build -v -o rate
+
+FROM alpine:latest
+RUN apk --no-cache add ca-certificates
+
+WORKDIR /app
+COPY --from=builder /build/rate rate
+
+CMD ["/app/rate"]