Convert string to underscored slug

Slugify

module Slugify
  
  def slugify(string)
    
    # Strip the string
    ret = string.strip

    # Blow away apostrophes
    ret.gsub! /['`]/,""

    # @ --> at, and & --> and
    ret.gsub! /\s*@\s*/, " at "
    ret.gsub! /\s*&\s*/, " and "

    # Replace all non-alphanumeric or periods with underscore
    ret.gsub! /\s*[^A-Za-z0-9\.]\s*/, '_'  

    # Replace hyphens with underscore
    ret.gsub! /\-/, "_"
    
    # Convert double underscores to single
    ret.gsub! /_+/,"_"

    # Strip off leading/trailing underscore
    ret.gsub! /\A[_\.]+|[_\.]+\z/,""
    
    ret
  end
   
end