Friendly_id problems on deploy / gemfile config

Friendly_id problems on deploy / gemfile config

With this config for friendly_id, I have troubles deplying on Ubuntu 13.04
x64
gem 'friendly_id', github: 'FriendlyId/friendly_id', branch: 'rails4'
A deploy cold results in the following :
[out :: xxx.fr] fatal: Could not parse object
'c49ce30ff2b370669ccf1708e99fb08ab51435d9'.
** [out :: xxx.fr]
** [out :: xxx.fr] Git error: command `git reset --hard
c49ce30ff2b370669ccf1708e99fb08ab51435d9`
** [out :: xxx.fr]
** [out :: xxx.fr] in directory
** [out :: xxx.fr]
** [out :: xxx.fr]
/home/deploy/public/xxx.fr/shared/bundle/ruby/1.9.1/bundler/gems/friendly_id-c49ce30ff2b3
** [out :: xxx.fr]
** [out :: xxx.fr] has failed.
** [out :: xxx.fr]
** [out :: xxx.fr] If this error persists you could try removing the
cache directory
** [out :: xxx.fr]
** [out :: xxx.fr]
'/home/deploy/public/xxx.fr/shared/bundle/ruby/1.9.1/cache/bundler/git/friendly_id-6a872655cfc7b9b88ea2b4131a9d102a429ae509'
** [out :: xxx.fr]
Thanks if any evidences of why this is happening !