I have created the step:
Given /^the feed \"([^\"]*)\" has an item \"([^\"]*)\" published at \"([^\"]*)\"$/ do |feed_name, feed_item_title, published_at|
f
In your step you need the " " around Twitter so use it same about Majbrasa
Scenario: feed items should be sorted by date
Given I am signed into an account called "GT" as a customer
And there is a social feed called "Twitter" for the account "GT"
And the feed "Twitter" has an item "Majbrasa" published at "2010-05-01"