Docker ubuntu with Swift

Dockerfile

FROM ubuntu:latest
RUN apt-get update && apt-get -y upgrade && apt-get install -y \
    git \
    zsh \
    vim \
    wget \
    clang \
 && apt-get clean \
 && rm -rf /var/lib/apt/lists/*

RUN git clone --recursive https://github.com/sorin-ionescu/prezto.git "${ZDOTDIR:-$HOME}/.zprezto"
COPY ./.zshrc /
RUN chsh -s /bin/zsh
RUN /bin/zsh -c "source /.zshrc"
RUN sed -ri "s/theme 'sorin'/theme 'skwp'/g" ~/.zpreztorc
RUN sed -ri "s/'prompt'/'prompt' 'syntax-highlighting' 'history-substring-search' 'git'/g" ~/.zpreztorc
RUN zsh
CMD ["zsh"]

RUN wget -q -O - https://swift.org/keys/all-keys.asc | gpg --import -
RUN wget https://swift.org/builds/ubuntu1404/swift-2.2-SNAPSHOT-2015-12-01-b/swift-2.2-SNAPSHOT-2015-12-01-b-ubuntu14.04.tar.gz -O swift.tar.gz
RUN wget https://swift.org/builds/ubuntu1404/swift-2.2-SNAPSHOT-2015-12-01-b/swift-2.2-SNAPSHOT-2015-12-01-b-ubuntu14.04.tar.gz.sig -O swift.tar.gz.sig
RUN gpg --keyserver hkp://pool.sks-keyservers.net --refresh-keys Swift
RUN gpg --verify swift.tar.gz.sig && mkdir /swift && tar -xzf swift.tar.gz -C /swift/ --strip-components=1
RUN export PATH=/swift/usr/bin:"${PATH}"
RUN echo "PATH=/swift/usr/bin:"${PATH}"" >> ~/.zshrc