def concat_url(parts)
      parts.reject!(&:empty?)
      if parts.length > 1
        parts.first + '?' + parts.drop(1).join('&')
      else
        parts.first
      end
    end
def concat_url(parts)
      parts.reject!(&:empty?)
      if parts.length > 1
        parts.first + '?' + parts.drop(1).join('&')
      else
        parts.first
      end
    end
Assemble a url from an array of parts.
 @param parts [Array] the url chunks to be assembled
 @return [String] the resultant url string