我的系统是Centos6.7的，我完全按照文档：https://gitlab.com/gitlab-org/gitlab-recipes/tree/master/install/centos，来进行安装。
当进行到Gems的安装步骤时，出问题了。

cd /home/git/gitlab

# For PostgreSQL (note, the option says "without ... mysql")
sudo -u git -H bundle config build.pg --with-pg-config=/usr/pgsql-9.3/bin/pg_config
sudo -u git -H bundle install --deployment --without development test mysql aws

执行：sudo -u git -H bundle install --deployment --without development test mysql aws,报错提示：

An error occurred while installing charlock_holmes (0.6.9.4), and Bundler cannot continue.
Make sure that `gem install charlock_holmes -v '0.6.9.4'` succeeds before bundling.

然后按照提示，安装charlock_holmes：

gem install charlock_holmes -v '0.6.9.4'

安装成功，执行gem list可以看到：

*** LOCAL GEMS ***

bigdecimal (1.2.4)
bundler (1.11.2)
charlock_holmes (0.6.9.4)
....

然后重新执行命令：

sudo -u git -H bundle install --deployment --without development test mysql aws

结果还是报错，说没有安装charlock_holmes :

An error occurred while installing charlock_holmes (0.6.9.4), and Bundler cannot continue.
Make sure that `gem install charlock_holmes -v '0.6.9.4'` succeeds before bundling.

实际上charlock_holmes已经安装成功了。

当然除了这个报错，我还看到安装过程中的报错信息，分别有两条，可能跟权限有关系：

Installing charlock_holmes 0.6.9.4 with native extensions

Errno::EACCES: Permission denied @ rb_sysopen - /home/git/gitlab/vendor/bundle/ruby/2.1.0/gems/charlock_holmes-0.6.9.4/.gitignore

Installing rugged 0.21.2 with native extensions

Errno::EACCES: Permission denied @ rb_sysopen - /home/git/gitlab/vendor/bundle/ruby/2.1.0/gems/rugged-0.21.2/LICENSE

请问，这是什么原因？