Missing spec for 1-types-validation

[iarie]

Hey @timriley, just started to explore workshop-app and i liked it!
1-types-validation: I guess there is a missing spec for this exercise:

Add a high-level rule to validate that published_at is filled only when status is set to "published"

like so:

it "rejects published_at if status is not 'published'" do
  result = schema.({title: "my article", status: "draft", published_at: Time.now}))
  expect(result).to be_failure
  expect(result.messages[:published_at_then_published].length).to eq 1
end

Or maybe make it xit and left as optional to encourage to implement rspec example