Add update documentation

README.md

@@ -29,6 +29,8 @@ sudo gitlab-ctl reconfigure
 sudo lokkit -s http -s ssh
 ```
+For update instructions, see [the update guide](doc/update.md).
+
 ## How to manage an Omnibus-installed GitLab
 ### Start/stop GitLab

doc/update.md

+# Updating GitLab via omnibus-gitlab
+
+## Updating from GitLab 6.6.0.pre1 to 6.6.4
+
+First, download the latest package from https://www.gitlab.com/downloads/ to your GitLab server.
+
+```shell
+# Stop unicorn and sidekiq so we can do database migrations
+sudo gitlab-ctl stop unicorn
+sudo gitlab-ctl stop sidekiq
+
+# One-time migration because we changed some directories since 6.6.0.pre1
+sudo mkdir -p /var/opt/gitlab/git-data
+sudo mv /var/opt/gitlab/{repositories,gitlab-satellites} /var/opt/gitlab/git-data/
+sudo mv /var/opt/gitlab/uploads /var/opt/gitlab/gitlab-rails/
+
+# Install the latest package
+# Ubuntu:
+sudo dpkg -i gitlab_6.6.4-omnibus.xxx.deb
+# CentOS:
+sudo rpm -Uvh gitlab-6.6.4_xxx.rpm 
+
+# Reconfigure GitLab (includes database migrations)
+sudo gitlab-ctl reconfigure
+
+# Start unicorn and sidekiq
+sudo gitlab-ctl start
+```
+
+Done!