airblade/vim-gitgutter — pull request #28 by scintill (2013-03-06 06:03:12+00:00)
Title: Allow user to define the signs.

Beware, I'm a vimscript novice. I just copied the pattern for user-defined highlights and this seems to be working for me.

I removed the call to define_signs() in update_line_highlights() -- if it's necessary to redefine them there, I guess we have to figure out a way to do that.