Problem:

Hound uses Rubocop under the hood to check for Ruby style violations.
Its [default config] is different from Rubocop's defaults.
This means that people who run rubocop locally
will get different feedback than they get from Hound.

[default config]: https://raw.githubusercontent.com/thoughtbot/hound/master/config/style_guides/ruby.yml

Solution:

Rename `.ruby-style.yml` to `.rubocop.yml`,
so Rubocop automatically picks up the configuration when run locally.

Update the rubocop config to use [thoughtbot's default].

[thoughtbot's default]: https://github.com/thoughtbot/hound/blob/master/config/style_guides/thoughtbot/ruby.yml