add dockerfile

Dockerfile

@@ -0,0 +1,13 @@
+FROM alpine:3.14.2 AS build
+RUN apk add --no-cache g++ libx11-dev make
+WORKDIR /repo
+COPY . .
+RUN make
+# RUN make && chmod a+x ./xkblayout-state
+# Export to a minimal runtime image and run as an unprivileged user.
+FROM alpine:3.14.2
+RUN apk add --no-cache libstdc++ libx11
+USER 1000:1000
+WORKDIR /repo
+COPY --from=build --chown=1000:1000 /repo/xkblayout-state .
+ENTRYPOINT ["./xkblayout-state"]