build: add Dockerfile

Dockerfile

@@ -0,0 +1,18 @@
+FROM golang:1.15-buster AS build
+
+WORKDIR /go/src/changeloguru
+
+COPY go.mod .
+COPY go.sum .
+
+RUN go mod download
+
+COPY . .
+
+RUN go build -o /go/bin/changeloguru
+
+FROM gcr.io/distroless/base-debian10
+
+COPY --from=build /go/bin/changeloguru /
+
+ENTRYPOINT ["/changeloguru"]