Merge branch 'ci-commit-as-pipeline' into 'master'

Ci::Commit becomes a Pipeline object

1. Ci::Commit receives context: ref, :tag.
1. One Ci::Commit describes a one Pipeline
1. Pipeline is created from `.gitlab-ci.yml`
1. Pipeline is a ordered group of builds
1. We test MR against Pipeline
1. Pipelines have a separate view (https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/3703)
1. Pipeline can be triggered from UI (https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/3703)
1. Later we change `Trigger -> TriggerRequest -> Build` to `Trigger -> Pipeline` (future)
1. We add a Pipeline Hook that will be triggered on Pipeline status change  (future)
1. We extend notifications to use `Pipeline Hook` to send summary on pipeline changes (future)

After merging that I'll prepare a separate MR that will unify naming, database columns, table names:
```
Ci::Commit -> Pipeline
Ci::Build -> Build
CommitStatus -> Job
GenericCommitStatus -> ExternalJob

ci_commits -> pipelines
ci_builds -> jobs
```

This MR implements first 5 points.

This is made to solve this issue https://gitlab.com/gitlab-org/gitlab-ce/issues/14149.

See merge request !3653

1 files changed, 10 insertions, 5 deletions

diff --git a/app/controllers/projects/commit_controller.rb b/app/controllers/projects/commit_controller.rb
index 4d64a2d9884..a202cb38692 100644
--- a/app/controllers/projects/commit_controller.rb
+++ b/app/controllers/projects/commit_controller.rb
@@ -38,13 +38,13 @@ class Projects::CommitController < Projects::ApplicationController
   end
 
   def cancel_builds
-    ci_commit.builds.running_or_pending.each(&:cancel)
+    ci_builds.running_or_pending.each(&:cancel)
 
     redirect_back_or_default default: builds_namespace_project_commit_path(project.namespace, project, commit.sha)
   end
 
   def retry_builds
-    ci_commit.builds.latest.failed.each do |build|
+    ci_builds.latest.failed.each do |build|
       if build.retryable?
         Ci::Build.retry(build)
       end
@@ -99,8 +99,12 @@ class Projects::CommitController < Projects::ApplicationController
     @commit ||= @project.commit(params[:id])
   end
 
-  def ci_commit
-    @ci_commit ||= project.ci_commit(commit.sha)
+  def ci_commits
+    @ci_commits ||= project.ci_commits.where(sha: commit.sha)
+  end
+
+  def ci_builds
+    @ci_builds ||= Ci::Build.where(commit: ci_commits)
   end
 
   def define_show_vars
@@ -113,7 +117,8 @@ class Projects::CommitController < Projects::ApplicationController
     @diff_refs = [commit.parent || commit, commit]
     @notes_count = commit.notes.count
 
-    @statuses = ci_commit.statuses if ci_commit
+    @statuses = CommitStatus.where(commit: ci_commits)
+    @builds = Ci::Build.where(commit: ci_commits)
   end
 
   def assign_change_commit_vars(mr_source_branch)