```ruby
class String
  # Returns a-string-with-dashes when passed 'a string with dashes'.
  # All special chars are stripped in the process
  def to_url
    return if self.nil?

    self.downcase.tr("\"'", '').strip.gsub(/\W/, '-').tr(' ', '-').squeeze('-')
  end

  # A quick and dirty fix to add 'nofollow' to any urls in a string.
  # Decidedly unsafe, but will have to do for now.
  def nofollowify
    self.gsub(/<\s*a\s*(.+?)>/i, '<a \1 rel="nofollow">')
  end

  # Strips any html markup from a string
  TYPO_TAG_KEY = TYPO_ATTRIBUTE_KEY = /[\w:_-]+/
  TYPO_ATTRIBUTE_VALUE = /(?:[A-Za-z0-9]+|(?:'[^']*?'|"[^"]*?"))/
  TYPO_ATTRIBUTE = /(?:#{TYPO_ATTRIBUTE_KEY}(?:\s*=\s*#{TYPO_ATTRIBUTE_VALUE})?)/
  TYPO_ATTRIBUTES = /(?:#{TYPO_ATTRIBUTE}(?:\s+#{TYPO_ATTRIBUTE})*)/
  TAG = %r{<[!/?\[]?(?:#{TYPO_TAG_KEY}|--)(?:\s+#{TYPO_ATTRIBUTES})?\s*(?:[!/?\]]+|--)?>}
  def strip_html
    self.gsub(TAG, '').gsub(/\s+/, ' ').strip
  end

end
```

Tweak permalink transformation again so existing tests don't break
user
```ruby
class String
  # Returns a-string-with-dashes when passed 'a string with dashes'.
  # All special chars are stripped in the process
  def to_url
    return if self.nil?

    self.downcase.tr("\"'", '').gsub(/\W/, ' ').strip.tr_s(' ', '-').tr(' ', '-').sub(/^$/, "-")
  end

  # A quick and dirty fix to add 'nofollow' to any urls in a string.
  # Decidedly unsafe, but will have to do for now.
  def nofollowify
    self.gsub(/<\s*a\s*(.+?)>/i, '<a \1 rel="nofollow">')
  end

  # Strips any html markup from a string
  TYPO_TAG_KEY = TYPO_ATTRIBUTE_KEY = /[\w:_-]+/
  TYPO_ATTRIBUTE_VALUE = /(?:[A-Za-z0-9]+|(?:'[^']*?'|"[^"]*?"))/
  TYPO_ATTRIBUTE = /(?:#{TYPO_ATTRIBUTE_KEY}(?:\s*=\s*#{TYPO_ATTRIBUTE_VALUE})?)/
  TYPO_ATTRIBUTES = /(?:#{TYPO_ATTRIBUTE}(?:\s+#{TYPO_ATTRIBUTE})*)/
  TAG = %r{<[!/?\[]?(?:#{TYPO_TAG_KEY}|--)(?:\s+#{TYPO_ATTRIBUTES})?\s*(?:[!/?\]]+|--)?>}
  def strip_html
    self.gsub(TAG, '').gsub(/\s+/, ' ').strip
  end

end
```
assistant