Changed the Dockerfile to a multi-stage build process (to reduce size massively)

Dockerfile

@@ -1,8 +1,9 @@
-FROM alpine
+# image for building the binary from source
+FROM alpine AS cmatrixbuildimage
 
 LABEL org.opencontainers.image.authors="bluefox@privacynerd.de"
 
-WORKDIR cmatrix
+WORKDIR /cmatrix
 
 RUN apk update && \
     apk add git autoconf automake alpine-sdk ncurses-dev ncurses-static && \
@@ -13,3 +14,13 @@ RUN apk update && \
     make
 
 CMD ["./cmatrix"]
+
+
+# final cmatrix Container Image
+FROM alpine
+
+LABEL org.opencontainers.image.authors="bluefox@privacynerd.de"
+
+COPY --from=cmatrixbuildimage /cmatrix/cmatrix /cmatrix
+
+CMD [".cmatrix"]