def underscore_string(str)
        str.to_s.strip.
          gsub(' ', '_').
          gsub(/::/, '/').
          gsub(/([A-Z]+)([A-Z][a-z])/,'\1_\2').
          gsub(/([a-z\d])([A-Z])/,'\1_\2').
          tr("-", "_").
          squeeze("_").
          downcase
      end
def underscore_string(str)
        str.to_s.strip.
          gsub(' ', '_').
          gsub(/::/, '/').
          gsub(/([A-Z]+)([A-Z][a-z])/,'\1_\2').
          gsub(/([a-z\d])([A-Z])/,'\1_\2').
          tr("-", "_").
          squeeze("_").
          downcase
      end
converts a camel_cased string to a underscore string
 subs spaces with underscores, strips whitespace
 Same way ActiveSupport does string.underscore