Redmine

Hi,

I've got a small problem, I'm trying to add some plugins to Redmine.

I've done all the step in the installation guide but for some reasons the plugins aren't showing up in plugin list of the administration panel.
I've check the logs of Redmine and my database, I don't see any errors and all the tables needed have been successfully created.

I've reinstall Redmine 3 times but it's always the same result, I can't add any plugins.

Can someone help me please?

Here's my environment informations :

Environment:
  Redmine version                3.1.0.stable
  Ruby version                   2.1.5-p273 (2014-11-13) [x86_64-linux-gnu]
  Rails version                  4.2.3
  Environment                    production
  Database adapter               Mysql2
SCM:
  Filesystem                     
Redmine plugins:
  no plugin installed