feat: add Dockerfile (#5)

Dockerfile

@@ -0,0 +1,25 @@
+FROM golang:1.18.2-alpine3.16 as builder
+
+WORKDIR /app/lubimyczytacrss
+
+COPY go.mod go.sum ./
+RUN go mod download
+
+COPY . .
+RUN CGO_ENABLED=0 go build -o lubimyczytacrss .
+
+######## Start a new stage from scratch #######
+FROM alpine:3.16
+
+WORKDIR /app/lubimyczytacrss
+
+RUN apk --no-cache add ca-certificates
+
+COPY --from=builder /app/lubimyczytacrss/lubimyczytacrss .
+
+EXPOSE 9234/tcp
+
+HEALTHCHECK --interval=30s --timeout=10s --retries=3 \
+    CMD wget --no-verbose --tries=1 --spider http://localhost:9234/health || exit 1
+
+CMD ["./lubimyczytacrss"]