apt install postgresql # or mysql-server

apt install redmine redmine-pgsql # or redmine-mysql, or redmine-sqlite

apt install apache2 libapache2-mod-passenger
cp /usr/share/doc/redmine/examples/apache2-passenger-host.conf
  /etc/apache2/sites-available/redmine.conf
edit /etc/apache2/sites-available/redmine.conf
a2enmod passenger
a2ensite redmine.conf
service apache2 reload

username: admin password: admin