anchor.diff: -FROM ruby:2.4.1-alpine
  +FROM ruby:2.4.1-alpine3.6
   
   LABEL maintainer="https://github.com/tootsuite/mastodon" \
         description="A GNU Social-compatible microblogging server"
  
positive.code:     file \
      git \
      icu-libs \
      imagemagick@edge \
      libidn \
      libpq \
      nodejs-npm@edge \
      nodejs@edge \
      protobuf \
      su-exec \
      tini \
      yarn@edge \
   && update-ca-certificates \
   && wget -O libiconv.tar.gz "http://ftp.gnu.org/pub/gnu/libiconv/libiconv-$LIBICONV_VERSION.tar.gz" \
   && echo "$LIBICONV_DOWNLOAD_SHA256 *libiconv.tar.gz" | sha256sum -c - \
  
negative.code: 
  WORKDIR /mastodon
  
  RUN apk -U upgrade \
   && apk add -t build-dependencies \
      build-base \
      icu-dev \
  