```ruby
require 'sequel'

module PGQuilter
  class Topic < Sequel::Model
    one_to_many :patchsets

    SUBJECT_WAS_RE = /.*\(\s*was:?\s*([^)]+)\s*\)/

    def self.for_subject(subject)
      normalized_subject = self.normalize(subject)
      Topic.find_or_create(name: normalized_subject)
    end

    def self.normalize(subject)
      # 1. Look for '(was $subject) and normalize subject instead
      # 2. Strip '[HACKERS]'
      # 3. Replace \W with '-'
      if subject =~ SUBJECT_WAS_RE
        normalize subject.sub(SUBJECT_WAS_RE, '\1')
      end
      subject.gsub('[HACKERS]\s*', '').gsub(/\W/, '-')
    end

  end
end
```

Remove unneeded comments and improve subject normalization
user
```ruby
require 'sequel'

module PGQuilter
  class Topic < Sequel::Model
    one_to_many :patchsets

    SUBJECT_WAS_RE = /.*\(\s*was:?\s*([^)]+)\s*\)/

    def self.for_subject(subject)
      normalized_subject = self.normalize(subject)
      Topic.find_or_create(name: normalized_subject)
    end

    def self.normalize(subject)
      if subject =~ SUBJECT_WAS_RE
        normalize subject.sub(SUBJECT_WAS_RE, '\1')
      end
      subject.gsub(/(?:Re:|\[HACKERS\])\s*/, '').gsub(/\W/, '-')
    end

  end
end
```
assistant