how to install downloaded ruby tarball by ruby-install

if you got brew, brew install ruby-install or install ruby-install from here: https://github.com/postmodern/ruby-install

at first, run ruby-install --no-install-deps --no-download ruby 2.3.0, you will see filename, then you can download the ruby tarball from
http://cache.ruby-lang.org/pub/ruby/ or `https://mirrors.huaweicloud.com/ruby/ruby/

mv it to ~/src, then re-run the above ruby-install command

export PATH=$(brew --prefix curl)/bin:$PATH
export PATH=$(brew --prefix openssl)/bin:$PATH
export RUBY_CONFIGURE_OPTS="--with-openssl-dir=$(brew --prefix openssl)"
# For compilers to find openssl and readline (brew info openssl)
export LDFLAGS="-L $(brew --prefix openssl)/lib -L $(brew --prefix readline)/lib"
export CPPFLAGS="-I $(brew --prefix openssl)/include -I $(brew --prefix readline)/include"

add these to your bash_profile, install ruby with openssl