Add Dockerfiles for ZSH 5.3.1, 5.4.2, 5.5.1

docker/base-5.3.1/Dockerfile

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+FROM debian:stretch
+
+# We switched here to debian, as there seems no ZSH 5.3 in ubuntu.
+
+RUN \
+  apt-get update && \
+  echo 'golang-go golang-go/dashboard boolean false' | debconf-set-selections && \
+  DEBIAN_FRONTEND=noninteractive apt-get install -y \
+  curl \
+  git \
+  zsh=5.3.1-4+b2 \
+  mercurial \
+  subversion \
+  golang \
+  jq \
+  nodejs \
+  ruby \
+  python \
+  python-virtualenv \
+  sudo \
+  locales
+
+RUN adduser --shell /bin/zsh --gecos 'fred' --disabled-password fred
+# Locale generation is different in debian. We need to enable en_US
+# locale and then regenerate locales.
+RUN echo "en_US.UTF-8 UTF-8" > /etc/locale.gen
+RUN locale-gen "en_US.UTF-8"
+
+COPY docker/fred-sudoers /etc/sudoers.d/fred
+
+USER fred
+WORKDIR /home/fred
+ENV LANG=en_US.UTF-8
+ENV TERM=xterm-256color
+ENV DEFAULT_USER=fred
+ENV POWERLEVEL9K_ALWAYS_SHOW_CONTEXT=true
+
+RUN touch .zshrc
+
+CMD ["/bin/zsh", "-l"]

docker/base-5.4.2/Dockerfile

@@ -0,0 +1,35 @@
+FROM ubuntu:18.04
+
+RUN \
+  apt-get update && \
+  echo 'golang-go golang-go/dashboard boolean false' | debconf-set-selections && \
+  DEBIAN_FRONTEND=noninteractive apt-get install -y \
+  curl \
+  git \
+  zsh=5.4.2-3ubuntu3 \
+  mercurial \
+  subversion \
+  golang \
+  jq \
+  nodejs \
+  ruby \
+  python \
+  python-virtualenv \
+  sudo \
+  locales
+
+RUN adduser --shell /bin/zsh --gecos 'fred' --disabled-password fred
+RUN locale-gen "en_US.UTF-8"
+
+COPY docker/fred-sudoers /etc/sudoers.d/fred
+
+USER fred
+WORKDIR /home/fred
+ENV LANG=en_US.UTF-8
+ENV TERM=xterm-256color
+ENV DEFAULT_USER=fred
+ENV POWERLEVEL9K_ALWAYS_SHOW_CONTEXT=true
+
+RUN touch .zshrc
+
+CMD ["/bin/zsh", "-l"]

docker/base-5.5.1/Dockerfile

@@ -0,0 +1,35 @@
+FROM ubuntu:18.10
+
+RUN \
+  apt-get update && \
+  echo 'golang-go golang-go/dashboard boolean false' | debconf-set-selections && \
+  DEBIAN_FRONTEND=noninteractive apt-get install -y \
+  curl \
+  git \
+  zsh=5.5.1-1ubuntu1 \
+  mercurial \
+  subversion \
+  golang \
+  jq \
+  nodejs \
+  ruby \
+  python \
+  python-virtualenv \
+  sudo \
+  locales
+
+RUN adduser --shell /bin/zsh --gecos 'fred' --disabled-password fred
+RUN locale-gen "en_US.UTF-8"
+
+COPY docker/fred-sudoers /etc/sudoers.d/fred
+
+USER fred
+WORKDIR /home/fred
+ENV LANG=en_US.UTF-8
+ENV TERM=xterm-256color
+ENV DEFAULT_USER=fred
+ENV POWERLEVEL9K_ALWAYS_SHOW_CONTEXT=true
+
+RUN touch .zshrc
+
+CMD ["/bin/zsh", "-l"]