(1) Install prerequisites.

sudo apt update
sudo apt install autoconf bison build-essential libssl-dev libyaml-dev libreadline6-dev zlib1g-dev libncurses5-dev libffi-dev libgdbm5 libgdbm-dev

(2) Setup rbenv.

git clone https://github.com/rbenv/rbenv.git ~/.rbenv

echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bashrc

echo 'eval "$(rbenv init -)"' >> ~/.bashrc

source ~/.bashrc

git clone https://github.com/rbenv/ruby-build.git ~/.rbenv/plugins/ruby-build

(3) Build ruby.

rbenv install 2.6.3

(4) Set as global version.

rbenv global 2.6.3

(5) Install bundler

gem install bundler

(6) Install MySQL client

sudo apt install mysql-client libmysqlclient-dev

(7) Install Yarn / Node

curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -

echo "deb https://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list

sudo apt update && sudo apt install yarn