ItemReopsitory #most-revenue(x)

So we got it working this morning. Feel free to give it a once over. One question that I had was we noticed werid behavior with:

  expect(@repo.most_revenue(5).first).to be an_intance_of(Item) vs
  expect(@repo.most_revenue(5).first).to be_a Item

the former was failing and spitting out a long green dump of an item object with a slew of transaction objects nested inside. Not really sure what that was all about.