用rbenv给整个系统安装ruby（所有用户都可用）

下面安装步骤可以安装在/usr/local/rbenv下，所有用户都可以共享rbenv。

#rbenv安装（/usr/local/rbenv）

#安装依赖，需要root用户

yum install -y git

yum install -y readline-devel

yum install -y openssl-devel zlib-devel

yum install -y postgresql-devel

#关闭ssl验证，如果clone报ca错误，执行下面的即可

#git config --global http.sslVerify false

git clone https://github.com/sstephenson/rbenv.git /usr/local/rbenv

echo 'export RBENV_ROOT=/usr/local/rbenv'>/etc/profile.d/rbenv.sh

echo 'export PATH="$RBENV_ROOT/bin:$PATH"'>>/etc/profile.d/rbenv.sh

echo 'eval "$(rbenv init -)"'>>/etc/profile.d/rbenv.sh

git clone https://github.com/sstephenson/ruby-build.git /usr/local/rbenv/plugins/ruby-build

#重新加载profile

source ~/.bash_profile

#查看可用ruby版本

rbenv install --list

#安装某一版本

rbenv install 2.1.5

rbenv global 2.1.5

#使用国内gem源

gem sources --remove https://rubygems.org/

#gem sources -a http://ruby.sdutlinux.org/

gem sources -a https://ruby.taobao.org/

gem sources -l

gem install bundle -V