install lib
brew install openssl libyaml libffi
install ruby
CONFIGURE_OPTS="--with-readline-dir=`brew --prefix readline` --with-openssl-dir=`brew --prefix openssl`" RUBY_CONFIGURE_OPTS="--with-readline-dir=`brew --prefix readline` --with-openssl-dir=`brew --prefix openssl`" rbenv install 1.8.7-p371