This application is setup using Docker and docker-compose, meaning you don't even need to have Ruby or any of the dependencies installed locally – you only need the Docker Toolbox.
Once you have the toolbox installed and running, you can boot the application by simply running ./bin/boot. docker-compose will take care of downloading and installing dependencies.
For your common commands, you'll need to use the script equivalents in the bin folder, e.g. ./bin/bundle exec ..., ./bin/rails generate ..., ./bin/rake db:migrate etc.
Tests can be run simply by using ./bin/rspec.
If you need to run a custom command, you can use ./bin/run command here, e.g. ./bin/run bash will give you a bash console.