Extending Lilypond's chord vocabulary

[lilypond]

How can I add a new chord to Lilypond's "chordmode" vocabulary?

A minor augmented triad is composed of a root, a minor third, and
an augmented fifth.  On lead sheets, I would like the markup to
be something like:

markup {
  \text "m"
  \super "aug"
}

How would I reference this chord in chordmode?  Perhaps

f:m.5+

or 

f:maug

would be convenient.

I have accomplished some basic chord *naming* alterations,
following an example snippet in the documentation:

- - -
chExceptionMusic = {
  <c ees ges bes>1-\markup {
    \text "m"
    \super { "7" \musicglyph #"accidentals.flat" "5" }
  }
  <c e g b d'>1-\markup {
    \super "maj9"
  }
}

% Convert music to list and prepend to existing exceptions.
chExceptions = #( append
  ( sequential-music-to-chord-exceptions chExceptionMusic #t)
  ignatzekExceptions)
- - -

But adding a new chord (and a new chordmode identifier for it)
appears to be a whole different ball of wax.

Can someone who has done this before offer some insight on how
they did it?

Thank you!

Jim