build: add docker build setup

Dockerfile

@@ -0,0 +1,26 @@
+FROM golang:1.23-alpine AS builder
+
+WORKDIR /usr/src/app
+
+# 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 go build -v ./main.go
+
+FROM alpine
+
+COPY --from=builder /usr/src/app/main /usr/bin/miniflux-archiver
+
+ENV MFA_CRON="* * * * *"
+
+WORKDIR /app
+
+COPY ./entrypoint.sh .
+
+ENTRYPOINT ["./entrypoint.sh"]
+
+RUN chmod +x entrypoint.sh /usr/bin/miniflux-archiver
+
+CMD ["--help"]