This needs to be done that way, because the committed_at can be null for some pretty old commits.

    * Move existing Slack service spec into a subdir, mirroring /app
    * Wire up HipChat service to the project and services controller.
    * Split the message building into own class.
    * 'namespace' room and token variables.
    * Enforce v2 client (bug in HipChat gem v1.5.0. fixed in 1.5.1). Note
      that I'm using the same version string as GitLab-CE, for shared
      installations.
    * Defer execution to a notifier worker, like the Slack service.
    * Ensure passing specs (basically a Slack service spec copy, fwiw)
    * Added change to the CHANGELOG

* Added rspec tests for #skip_ref?
* Allow regex matching
* Added hints on Project form

- Send notification at once for all commits