custom attributes per file

Hi git devs,

I have seen on your TODO list, that you plan to add tree attributes. We 
want to use git as a backend to store the wikipedia content in a 
distributed manner. The exporter [1] is already quite stable it seems. 
Today I started a frontend project [2] and have a feature request :-)

* Make attributes apply to trees, not just working tree.

What we need are versioned attributes per file and per tree. Currently 
we export each article into a file, but there is no way we could save 
custom attributes directly bound to it, which distributes the data which 
should be together. If the maximum value per attribute should be quite 
large, this way we could save reports of vote results bound to the 
article directly.

I think unicode data to an ascii key would be sufficient, but real types 
could provide great features in the future. Changes to these values 
should be signable by gpg signed commit messages like a normal checkin.

Maybe in the long run, there could be some sort of export filter 
mechanism. For cloning repositories, for example a copy of the wiki 
database based on a quality key of an article could be exported for a 
embedded device.

[1] http://github.com/scy/levitation
[2] http://github.com/poelzi/communiki

kindly regards
  Daniel Poelzleithner