$ ssh root@IP_ADRESS 

$ yum update

$ adduser kabigon
$ passwd kabigon
# enter password

$ exit

$ ssh kabigon@IP_ADRESS

$ su -

$ cd /etc/ssh
$ cp sshd_config sshd_config.old
$ vim sshd_config

PermitRootLogin yes -> PermitRootLogin no

$ systemctl restart sshd.service

$ exit
$ ssh root@IP_ADRESS 
# can not login

$ yum -y install openssl-devel readline-devel zlib-devel libcurl-devel make openssl-devel
$ yum -y install gcc-c++ glibc-headers openssl-devel readline libyaml-devel readline-devel zlib
$ yum -y install git gcc make openssl-devel libffi-devel sqlite sqlite-devel nodejs

$ cd /opt
$ git clone https://github.com/rbenv/rbenv.git

$ mkdir /opt/rbenv/plugins
$ cd /opt/rbenv/plugins
$ git clone https://github.com/rbenv/ruby-build.git

$ cat << 'EOS' > /etc/profile.d/rbenv.sh
export RBENV_ROOT="/opt/rbenv"
export PATH="${RBENV_ROOT}/bin:${PATH}"
eval "$(rbenv init -)"
EOS

exec $SHELL -l

$ rbenv install 2.5.1
$ rbenv global 2.5.1
$ ruby -v

$ gem install rails
$ cd
$ rails new myApp
$ cd myApp

$ rails s
$ control + z
$ jobs
$ bg 1
$ curl localhost:3000

yum -y install nginx
systemctl enable nginx.service
systemctl start nginx.service
systemctl status nginx.service

$ firewall-cmd --add-service=http --permanent
$ firewall-cmd --reload

$ cd /etc/nginx
$ vi nginx.conf

listen          80;
listen          [::]:80;
servername      0.0.0.0;

...

location / {
        proxy_pass http://localhost:3000;
}

$ systemctl restart nginx.service