Installing Ruby
Before you can install Spina, you need to have Ruby and Rails installed first. Here are a couple of excellent resources to do that:
If you're on a Mac you should something like rbenv to manage different versions of Ruby.
Database
You need a database to store all of your content. Spina CMS requires a PostgreSQL database. You can install it using several ways. If you're on a Mac we recommend using homebrew so you can simply run brew install postgresql.