Add build dockerfile

Dockerfile

@@ -0,0 +1,17 @@
+FROM golang:1.21 as build
+
+WORKDIR /godoor
+
+# pre-copy/cache go.mod for pre-downloading dependencies and only redownloading them in subsequent builds if they change
+COPY go.mod go.sum ./
+RUN go mod download && go mod verify
+
+
+COPY . .
+RUN make build
+
+FROM scratch
+WORKDIR /
+COPY --from=build /godoor/godoor /godoor
+
+ENTRYPOINT ["/godoor"]