Dockerizing segvan

[kaplanmaxe]

This PR adds docker to segvan. The idea behind this is that an image can be pushed to docker hub and a user could simply pull down the image and not have to worry about installation. Instructions have been added to README.md.

[matthewincognito]

Maybe it would be better if you did a multi-stage build, the first one a static build and the second one FROM scratch. The image be much smaller and wouldn't have any extra layers to pull in.

Something like this:

FROM alpine:edge AS builder

RUN apk add --no-cache \
    build-base \
    cmake \
    git \
    libuv-dev \
  && git clone https://github.com/xmrig/xmrig.git /xmrig \
  && mkdir /xmrig/build \
  && cd /xmrig/build \
  && cmake .. \
    -DCMAKE_BUILD_TYPE=Release \
    -DWITH_HTTPD=OFF \
    -DCMAKE_EXE_LINKER_FLAGS="-static" \
    -DCMAKE_FIND_LIBRARY_SUFFIXES=".a" \
  && make -j$(nproc) \
  && strip ./xmrig

FROM scratch

COPY --from=builder /xmrig/build/xmrig /

ENTRYPOINT ["/xmrig"]

[kaplanmaxe]

@matthewincognito Thanks for the feedback! This could work as well... didn't spend much time on it. I don't think saving a few mbs here in the image is all that important considering it's not going into a production environment or anything. I guess I will leave it up to the maintainer.