anchor.diff:  FROM centos:centos6
   MAINTAINER pepechoko
   
  -RUN yum update -y
  -RUN rpm -Uvh http://download.fedoraproject.org/pub/epel/6/i386/epel-release-6-8.noarch.rpm
  -RUN yum install -y \
  +RUN 
  +  yum update -y && \
  +  apt-get clean && \
  +  rm -rf /var/cache/apt/archives/* /var/lib/apt/lists/* 
  +
  +RUN \
  +  rpm -Uvh http://download.fedoraproject.org/pub/epel/6/i386/epel-release-6-8.noarch.rpm
  +
  +RUN yum install -y --no-install-recommends \
     autoconf \
     automake \
     curl-devel \
  
positive.code:   libxslt-devel \
    libyaml-devel \
    make \
    openssh \
    openssh-clients \
    openssh-server \
  
negative.code:   tar \
    tree \
    which \
    zlib-devel
  
  ## add rbenv group
  RUN groupadd rbenv
  