anchor.diff:  FROM heroku/cedar:14
   
  -# Dependencies
  -RUN apt-get update && apt-get install -y --no-install-recommends \
  -    bzip2 \
  -    ca-certificates \
  -    curl \
  -    gcc \
  -    libc6-dev \
  -    libgmp-dev \
  -    libgmp10 \
  -    make \
  -    patch \
  -    zlib1g-dev \
  +ENV GHCVER 7.8.4
  +ENV CABALVER 1.18
  +
  +RUN apt-get update && apt-get install -y --no-install-recommends software-properties-common \
  +  && add-apt-repository -y ppa:hvr/ghc \
  +  && apt-get update \
  +  && apt-get install -y --no-install-recommends \
  +    cabal-install-$CABALVER \
  +    ghc-$GHCVER \
     && rm -rf /var/lib/apt/lists/*
   
  -# GHC
  -RUN mkdir -p /usr/src/ghc
  -WORKDIR /usr/src/ghc
  -
  -RUN curl --silent -O https://downloads.haskell.org/~ghc/7.10.1/ghc-7.10.1-x86_64-unknown-linux-deb7.tar.bz2 \
  -  && echo '3f513c023dc644220ceaba15e5a5089516968b6553b5227e402f079178acba0a  ghc-7.10.1-x86_64-unknown-linux-deb7.tar.bz2' | sha256sum -c - \
  -  && tar --strip-components=1 -xjf ghc-7.10.1-x86_64-unknown-linux-deb7.tar.bz2 \
  -  && rm ghc-7.10.1-x86_64-unknown-linux-deb7.tar.bz2 \
  -  && ./configure --prefix=/opt/ghc \
  -  && make install \
  -  && rm -rf /usr/src/ghc \
  -  && /opt/ghc/bin/ghc --version
  -
  -ENV PATH /opt/ghc/bin:$PATH
  -
  -# Cabal
  -RUN mkdir -p /usr/src/cabal
  -WORKDIR /usr/src/cabal
  -
  -RUN curl --silent -O https://www.haskell.org/cabal/release/cabal-install-1.22.2.0/cabal-install-1.22.2.0.tar.gz \
  -  && echo '25bc2ea88f60bd0f19bf40984ea85491461973895480b8633d87f54aa7ae6adb  cabal-install-1.22.2.0.tar.gz' | sha256sum -c - \
  -  && tar --strip-component=1 -xzf cabal-install-1.22.2.0.tar.gz \
  -  && rm cabal-install-1.22.2.0.tar.gz \
  -  && /usr/src/cabal/bootstrap.sh \
  -  && cp /root/.cabal/bin/cabal /opt/ghc/bin \
  -  && for pkg in `ghc-pkg --user list  --simple-output`; do ghc-pkg unregister --force $pkg; done \
  -  && rm -rf /root/.cabal \
  -  && rm -rf /usr/src/cabal \
  -  && cabal --version
  +ENV PATH /opt/ghc/$GHCVER/bin:/opt/cabal/$CABALVER/bin:$PATH
   
   # Create app user, required? by Heroku
   RUN useradd -d /app -m app
  
positive.code: ENV HOME /app
  ENV PORT 3000
  
  RUN cabal update && cabal install 'warp >=3.0' 'wai-app-static >=3.0' 'waitra >=0.0.3'
  
  # Build the app
  ONBUILD COPY . /app/src
  
negative.code: ONBUILD USER app
  
  ONBUILD WORKDIR /app/src
  ONBUILD RUN stackage-update
  ONBUILD RUN cabal install
  
  ONBUILD RUN mkdir -p /app/target && cp $HOME/.cabal/bin/heroku-docker-haskell-test /app/target/heroku-docker-haskell-test
  