This assumes you have a twilio account and have purchased/reserved a phone number...

If you are using bundler add the following line to your Gemfile to include twilio-ruby in your project:

gem 'twilio-ruby'

otherwise enter gem install twilio-ruby on the command line. You might need sudo if you're using system Ruby and not ruby-env etc.

and the code

# Instantiate a Twilio REST client with your account SID and auth token,
# which can be found on your dashboard.

client = Twilio::REST::Client.new("your_account_sid", "your_auth_token")

client.messages.create(from: "+15556667777", to: "+15558883333", body: "Hello, world!")