Refractometer

DLS for Refractometer tool

```ruby
american_ipa = Brewery.guides(:bjcp).find(id: '14B')

tool = Brewery.tools :refractometer do
  style american_ipa

  original_brix 17
  final_brix 7.5
end
```

You can search style by style ID

```ruby
tool = Brewery.tools :refractometer do
  style '14B'

  original_brix 17
  final_brix 7.5
end
```

That's it!

```ruby
tool.original_gravity
# => 1.0706483000102098

tool.final_gravity
# => 1.0049822062500002

tool.alcohol_by_weight
# => 6.734352775327011

tool.alcohol_by_volume
# => 8.523809458203969
```