My preferred Rubocop setup.

rubocop.yml

AllCops:
  Excludes:
    - setup_environment.rb

# Prefer a comma at the end of a multiline, to minimise diff changes and
# enable easier rearranging of lines.
TrailingComma:
  EnforcedStyleForMultiline: comma

# Experimenting with the idea of having the `private`, `protected`
# declarations be at the same level of indent as the `class` keyword.
AccessModifierIndentation:
  EnforcedStyle: outdent

# Don't bother complaining that utf-8 hasn't been specified as the encoding
# for every file.
Encoding:
  Enabled: false

# The style guide claims multi-line chaining is "always ugly". Maybe.
# I happen to tolerate it in moderation.
Blocks:
  Enabled: false