Add project management link to commit message

* Create a connection between project management system and git history.
* Make it easy for future developers to understand the reasons why code
  exists without having to disturb the original author or relying on the
  original author being available/on the project/not sick/not on
  vacation/ with the company at a later date.
* It requires little effort (10-20 seconds) to add the link.
* It encourages a ticket/story for commits.

https://github.com/thoughtbot/guides/pull/40