anchor.diff:  WORKDIR $HOME
   RUN git clone https://github.com/obgm/libcoap.git
   WORKDIR $HOME/libcoap
  -RUN git checkout f1a5435193131ea0edbbdf2558d61244a768c961
  +RUN git checkout 6fc3a7315f6629d804cc7928004cddeb4a84443c
   RUN ./autogen.sh
   RUN ./configure --disable-documentation --with-openssl
   RUN make && make install
  
positive.code: RUN apt-get update && apt-get -y install wget curl git build-essential autoconf automake libtool pkg-config gnutls-bin sudo vim
  RUN apt-get install -q -y libmysqld-dev
  
  # install go1.13.3
  RUN wget https://dl.google.com/go/go1.13.3.linux-amd64.tar.gz && tar -C /usr/local -xzf go1.13.3.linux-amd64.tar.gz
  RUN mkdir $HOME/go
  ENV PATH $PATH:/usr/local/go/bin
  ENV GOPATH $HOME/go
  
negative.code: FROM ubuntu:18.04
  
  USER root
  ENV HOME /home
  