Style/HashSyntax: Use the new Ruby 1.9 hash syntax. (https://rubystyle.guide#hash-literals)

Style/StringLiterals: Prefer double-quoted strings unless you need single quotes to avoid extra backslashes for escaping. (https://rubystyle.guide#consistent-string-literals)

Bundler/OrderedGems: Gems should be sorted in an alphabetical order within their section of the Gemfile. Gem `terser` should appear before `uglifier`.