post.rb

# Certain methods require authentication. To get your Twitter OAuth credentials,
# register an app at http://dev.twitter.com/apps
Twitter.configure do |config|
  config.consumer_key = YOUR_CONSUMER_KEY
  config.consumer_secret = YOUR_CONSUMER_SECRET
  config.oauth_token = YOUR_OAUTH_TOKEN
  config.oauth_token_secret = YOUR_OAUTH_TOKEN_SECRET
end

# Update your status
Twitter.update("I'm tweeting from the Twitter Ruby Gem!")