So, While I still not understand why it didn't worked before, I totally changed my approach and now it's working. I have a #git #gitweb instance ! Nice :) The main goal was to symlink it to the external drive since the main board has only 4go of disk in total and it's done. Yay !

Behold ! My gitweb instance : https://git.geno.is

For now only a test repo and an other of a game I'm making.