(This isn't  specifically a Textmate question, but I know a lot of Textmate users use Markdown, so I was hoping someone could help.)

How do I name Markdown files so that they are:

  1) Recognized automatically by Textmate as Markdown files when you open them,
  2) Indexed automatically by Spotlight,
  3) Use a unique extension (like .markdown) rather than a generic .txt extension?

Right now, if I use the default .markdown extension, the file isn't indexed by Spotlight.  If I save a Markdown file without any extension, it's neither indexed by Spotlight, nor is it recognized by Textmate as a Markdown file.

A .txt extension is recognized by Textmate and indexed by Spotlight, but I was hoping to use a different file extension--one that could distinguish Markdown files from other text files.

How do other people solve this problem?

Thanks,
Tom