update ruby version

cng@ACP:/opt/newdisk/mydockers/docker-lamp$ source /usr/local/rvm/scripts/rvm cng@ACP:/opt/newdisk/mydockers/docker-lamp$ rvm use 2.4.1 Using /home/chang/.rvm/gems/ruby-2.4.1 cng@ACP:/opt/newdisk/mydockers/docker-lamp$ ruby -v ruby 2.4.1p111 (2017-03-22 revision 58053) [x86_64-linux]