1.Install right ruby version rvm install ruby-1.9.2-p290 rvm use ruby-1.9.2-p290 rvm gemset create ruby-blog
2.Install PostgreSQL: sudo apt-get install postgresql pgadmin3 sudo apt-get install libpq-dev libpq5 sudo -u postgres psql postgres \password postgres sudo -u postgres createdb mydb
3.Install nokogiri dependencies: sudo apt-get install libxml2 libxml2-dev libxslt1.1 libxslt1-dev
4.Create database.yml Just copy database.yml.example and configure your db setup
5.Finishing installation bundle install rake db:create rake db:migrate rake data:admin
Now go to http://your_host/administration/admins to create new posts/admins etc.
Have fun