cookbook assignment

Would appreciate any suggestions on refactoring or ways of simplifying my code. This assignment was pretty hard for me and I think my messy code reflects that a bit. I also noticed a really weird bug yesterday that treats the recipe_id and ingredient_id as string values rather than integers. I have no idea why it is doing this!
This could use `ActiveRecord` association methods, the `has_many :usages` within the `Recipe` class gives us the ability to:

```ruby
@recipe = Recipe.find(params[:id])
@usages = @recipes.usages
```

Which would accomplish the same result.