Ubuntu 20.04 LTS でrbenvに必要なパッケージ
$ sudo apt install autoconf bison build-essential libssl-dev libyaml-dev libreadline-dev zlib1g-dev libncurses5-dev libffi-dev libgdbm6 libgdbm-dev
Passengerに必要なパッケージ
$ sudo apt install libcurl4-openssl-dev apache2-dev libapr1-dev libaprutil1-dev
