Dinodex feature

Notice how in `Controller` you only use `catalog` and that `Catalog` contains `@dinos`. This means you do not need to store `@dinos` in `Controller`. Your method `build_catalog` can build the dinosaurs as a local variable:

`def build_catalog`
`  dinos = standardized_data.map { |row| Dinosaur.new(row) }`
`  Catalog.new(dinos)`
`end`