Separate Commit model and logic from Build model|etc...

This is an entirely non-user facing change which prepares GitLab CI for future support of Parallel Builds.
See https://about.gitlab.com/2013/12/19/gitlab-ci-with-parallel-builds-and-deployments/.

These changes specifically avoid changing the supported API or changing any of the website views.
Changes to the website views will come in tandem with future features like "Multiple build scripts".
The supported API won't change as part of any future changes on this vein, to maintain support for the unofficial GitLab CI runners.

This closes the following implementation step:
1. A commit has many builds

Signed-off-by: Kestred <kestred@riotcave.com>
Bugfix: Fix gitlab stubs for archived projects.
Specify class for alert in views/layouts
Docker Image mention

As per conversation with @dosire, I'l like to add the mention of the GitLab-CI Docker image I've build.
I'm not exactly sure how you'd like to word it or section to place it within, so feel free to throw this away and use your own wording...
Thanks GitLabHQ
Merge pull request #483 from anapsix/patch-1

Docker Image mention
Add a comment about Whenever and omnibus packages
Look for a REVISION file before running `git log`
Merge branch 'revision_file' into 'master'

Look for a REVISION file before running `git log`

See merge request !76
Merge branch 'master' of github.com:gitlabhq/gitlab-ci
Also add Sameer his docker image.
Merge branch 'cron_comment' into 'master'

Add a comment about Whenever and omnibus packages

See merge request !75
New feature: All builds page for admin user

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Merge branch 'admin-builds-page'

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Conflicts:
	CHANGELOG
release 5.1
Merge branch '5-1-stable' into 'master'

5-1-stable to master

See merge request !78
Add rack profiler to development

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Fix migrations and add mysql limits

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Merge branch 'rack-profiler' into 'master'

Rack profiler

See merge request !79
Merge branch 'fix-migrations' into 'master'

Fix migrations

See merge request !80
Add indicies for better performance

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>