0. `blog.rosaceae.net`をDNSレコードに登録する
3. `/etc/nginx/sites-enabled/blog.rosaceae.net.conf`をつくる

    server {
        listen 80;
        listen [::]:80;
        server_name blog.rosaceae.net;
        return 301 https://$host$request_uri;
    }

    server {
        listen 443 ssl http2;
        listen [::]:443 ssl http2;
        server_name blog.rosaceae.net;
        ssl_certificate //;
        ssl_certificate_key /path/to/private_key;

    }

c.f. https://ssl-config.mozilla.org/#server=nginx&version=1.17.7&config=modern&openssl=1.1.1d&guideline=5.6

3. `sudo service nginx restart`