Welcome to the app! Clone locally and run bundle install && rake db:create db:schema:load
to get started. This assumes you have all components to run a rails app out of the box. If this is not the case then visiting http://www.moncefbelyamani.com/how-to-install-xcode-homebrew-git-rvm-ruby-on-mac/ may be helpful.
There is currently no set way to test Twilio functionality locally. If you end up working on this and need to test locally, look up setting up local tunnelling for your development machine and please update this doc with instructions.