Added Rake task for tracking deployments

What does this MR do?

This MR adds a Rake task to track the current version of GitLab in InfluxDB.

Are there points in the code the reviewer needs to double check?

We may want to document this Rake task in some Markdown file, but I'm not sure what the best place for this would be.

Why was this MR needed?

We want to have a more accurate overview of when deployments occurred.

What are the relevant issue numbers?

https://gitlab.com/gitlab-com/infrastructure/issues/98

Does this MR meet the acceptance criteria?

• CHANGELOG entry added
• Documentation created/updated
• API support added
• Conform by the style guides
• Branch has no merge conflicts with master (if you do - rebase it please)
• Squashed related commits together

mentioned in merge request influxdb-management!2 (merged)

@yorickpeterse Thanks, LGTM! We could probably add documentation in http://docs.gitlab.com/ee/raketasks/maintenance.html?

Added ~149423 label

Added 1 commit:

• 499cdf1d - Added Rake task for tracking deployments

@rymai Done!

Marked the task Documentation created/updated as completed

@yorickpeterse Awesome, thanks! We should also add this step in our deployment guides?

• https://dev.gitlab.org/cookbooks/chef-repo/blob/master/doc/staging.md
• https://dev.gitlab.org/cookbooks/chef-repo/blob/master/doc/deploying.md

Marked the task Branch has no merge conflicts with master (if you do - rebase it please) as completed

Status changed to merged

mentioned in commit 1e81ab7c

@rymai Ideally it's to be executed automatically, I was going to discuss this once this MR was merged.

mentioned in commit influxdb-management@2c561293

@yorickpeterse Awesome!

Picked into 8-10-stable, will go into 8.10.0-rc11.

Removed ~149423 label

mentioned in commit e8acbac3