def mime_type(type, value)
      type = ".#{type}" unless type.to_s[0] == '.'
      ::Rack::Mime::MIME_TYPES[type] = value
    end
def mime_type(type, value)
      type = ".#{type}" unless type.to_s[0] == '.'
      ::Rack::Mime::MIME_TYPES[type] = value
    end
Add a new mime-type for a specific extension

 @param [Symbol] type File extension
 @param [String] value Mime type
 @return [void]