anchor.diff: -FROM ubuntu:17.04
  +FROM ubuntu:18.04
   MAINTAINER Don Petersen <don@donpetersen.net>
   
   # Start by changing the apt output, as stolen from Discourse's Dockerfiles.
  
positive.code:     apt-get install -y openssh-server &&\
      mkdir /var/run/sshd &&\
      echo "AllowAgentForwarding yes" >> /etc/ssh/sshd_config &&\
  # Fix for occasional errors in perl stuff (git, ack) saying that locale vars
  # aren't set.
      apt-get install -y locales &&\
      locale-gen --purge en_US.UTF-8 &&\
      update-locale LANG=en_US.UTF-8
  
  RUN useradd dev -d /home/dev -m -s /bin/zsh &&\
      adduser dev sudo && \
      echo '%sudo ALL=(ALL) NOPASSWD:ALL' >> /etc/sudoers
  
  
negative.code: # Nobody is happy when these aren't up-to-date
      apt-get install -y ca-certificates &&\
  # Basic dev tools
      apt-get install -y openssh-client git build-essential ctags man curl direnv software-properties-common &&\
  # Set up for pairing with wemux.
      apt-get install -y tmux &&\
      git clone git://github.com/zolrath/wemux.git /usr/local/share/wemux &&\
  