It is a Rails application, so you would need to have Ruby installed. Check out https://www.driftingruby.com/episodes/getting-started-ruby-on-rails-development-environment on getting a non-system ruby installed on your environment. 

Then in the app root, you should be able to just do 

gem install bundler #installs bundle cli
bundle # installs gem dependencies
rake db:migrate # creates the SQLite3 Schema
rails s # starts the development server