anchor.diff:      tar \
       zlib-dev && \
     rm -rf /var/cache/apk/*
  +
  +# Install postgresql
  +RUN wget ftp://ftp.postgresql.org/pub/source/v$PG_VERSION/postgresql-$PG_VERSION.tar.bz2 -O /tmp/postgresql-$PG_VERSION.tar.bz2 && \
  +    tar xvfj /tmp/postgresql-$PG_VERSION.tar.bz2 -C /tmp && \
  +    cd /tmp/postgresql-$PG_VERSION && \
  +    ./configure --enable-integer-datetimes --enable-thread-safety --prefix=/usr/local --with-libedit-preferred --with-openssl && \
  +    make world && \
  +    make install world && \
  +    make -C contrib install && \
  +    cd /tmp/postgresql-$PG_VERSION/contrib && \
  +    make && make install && \
  +    rm -r /tmp/postgresql-$PG_VERSION*
   
   # Install ruby gems.
   RUN \
  
positive.code: ENV \
    HOME=/home/backups \
    BACKUP_CONFIG_DIR=/etc/backups \
    BACKUP_DATA_DIR=/var/lib/backups
  
  # Install base packages.
  RUN \
  
negative.code:     libxml2-dev \
      libxslt-dev \
      mysql-client \
      openssl-dev \
      readline-dev \
      redis \
      rsync \
      ruby \
  