add docker files

Dockerfile

@@ -0,0 +1,24 @@
+FROM golang:latest AS builder
+
+WORKDIR /app
+
+COPY . .
+
+RUN go mod download
+
+RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 \
+    go build -o uptimemonitor \
+    -ldflags "-X uptimemonitor/pkg/version.Version=$(git describe --tags)" \
+    ./cmd/uptimemonitor
+
+FROM alpine:latest
+
+WORKDIR /app
+
+RUN apk add --no-cache ca-certificates
+
+COPY --from=builder /app/uptimemonitor .
+
+EXPOSE 3000
+
+CMD ["./uptimemonitor"]