update ruby to latest version

steps for mac

install rvm

install

 $ curl -L get.rvm.io | bash -s stable
 ...
 Upgrade Notes:
 * WARNING: '~/.profile' file found. To load it into your shell, add the following line to '/Users/gree2/.bash_profile':
   source ~/.profile
 * No new notes to display.

check install

 $ source ~/.profile
 $ source ~/.bash_profile

 $ rvm -v

update ruby

check ruby version

 $ rvm -v
 rvm 1.29.3 (latest) by Michal Papis, Piotr Kuczynski, Wayne E. Seguin [https://rvm.io]

list ruby versions

 $ rvm list known
 # MRI Rubies
 ...
 [ruby-]2.2[.7]
 [ruby-]2.3[.4]
 [ruby-]2.4[.1]
 ...

install ruby
```
 $ rvm install 2.4.1
```

check ruby version

 $ ruby -v
 ruby 2.4.1p111 (2017-03-22 revision 58053) [x86_64-darwin16]

steps for centos

install rvm
1. add keys
  
  $ gpg2 –recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3
2. install rvm
  
  $ curl -L get.rvm.io bash -s stable
  
  Downloading https://github.com/rvm/rvm/archive/1.29.3.tar.gz Downloading https://github.com/rvm/rvm/releases/download/1.29.3/1.29.3.tar.gz.asc gpg: … … GPG verified ‘/usr/local/rvm/archives/rvm-1.29.3.tgz’ Creating group ‘rvm’
  
  Installing RVM to /usr/local/rvm/ Installation of RVM in /usr/local/rvm/ is almost complete:
  - First you need to add all users that will be using rvm to ‘rvm’ group, and logout - login again, anyone using rvm will be operating with umask u=rwx,g=rwx,o=rx.
  - To start using RVM you need to run source /etc/profile.d/rvm.sh in all your open shell windows, in rare cases you need to reopen all shell windows.
source and install
1. source
  
  $ source /etc/profile.d/rvm.sh $ rvm list known $ rvm install 2.3.4
2. change sources and install gems
  
  $ gem sources -l $ gem sources -r https://rubygems.org/ $ gem sources –add https://gems.ruby-china.org/ $ gem install bundler $ gem install rails $ gem install jekyll