* pipeline-hooks-without-slack: (156 commits)
  Fix test failures
  Make pipeline to be in created state for hooks tests
  Make `execute_methods` public
  Added specs for started_at and finished_at
  Use explicit events to transition between states
  Fix tests. We cannot reload unless it's already saved:
  Have trait all_events_enabled so that's easier to reuse, feedback:
  Simplify the name for data builder, feedback:
  Prefer extend self over module_function, feedback:
  Make it more grammatically correct, feedback:
  if -> when; when -> `when`; %w() -> %w[]; and fix some typos:
  Prefer described_class, feedback:
  Make the comment more clear, feedback:
  Update CHANGELOG
  render only commit title
  Fix test failures, that did occur because of missing previously used `reload_status!` call
  Use state machine for pipeline event processing
  Upgrade Rails to 4.2.7.1 for security fixes.
  Update gitlab-shell to v3.3.3
  Verify the pipeline status after executing events on builds
  ...