Document pipeline triggers

This is the continuation of https://dev.gitlab.org/gitlab/gitlab-ci/issues/282

The build trigger API https://gitlab.com/gitlab-org/gitlab-ci/merge_requests/229/diffs still needs to be documented (if I search pipeline or trigger on http://doc.gitlab.com/ce/ci/ I should find an entry)

BTW The tagging of builds mentioned in https://dev.gitlab.org/gitlab/gitlab-ci/issues/282#note_53301 is something we can also work on, but I'm sure it will come up. And I feel pretty happy with the tagging before a build that we do now.

Milestone changed to 8.2

cc @ayufan @axil

Added ~15078 label

Added ~19173 label

Title changed from Document piepline triggers to Document pipeline triggers

Milestone changed to 8.3

/cc @axil

Reassigned to @axil

Scheduling this for next week. I still need to read the discussion and then maybe make a call with @ayufan if I have any questions.

@axil what is the status of this?

@sytses I didn't have the time to see it, I moved it up in the list for Monday.

mentioned in merge request !2161 (merged)

@axil OK, thanks

Added ~122770 label

Status changed to closed by merge request !2161 (merged)

mentioned in commit ed777c7b

@axil please suggest message for @nearlythere to tweet

Status changed to reopened

@nearlythere I guess something between the lines of the text below should be ok. You can add some sprinkle like you know best :)

Did you know that the GitLab CI API supports triggering a rebuild for branches, tags, or specific commits? http://doc.gitlab.com/ce/ci/triggers/README.html

Thank you! Done :)

I'd love to brainstorm more of these feature highlight tweets.

Talk to you soon.

Status changed to closed

Thanks :)