First of all, rename the file config/database.yml.sample
mv config/database.yml.sample config/database.yml
and then, update it with your database connection parameters.
You will need to create a postgis template database. Here explain how to do it.
After that, you can proceed with the rest of the installation steps:
You need imagemagick ruby -e "$(curl -fsSL https://gist.github.com/raw/323731/install_homebrew.rb)"
brew install imagemagick
And the database:
This will take a while, since 1.4 million records must be inserted in the database.
To run the application in your development machine, just start the server
and load the app in your browser:
Now, time to hack and send some pull requests!