Add missing documentation.
Add missing documentation.

Build was being triggered but there was no documentation about it, so
I'm adding what I was receiving from webhooks when implementing the
Rocketchat integration (https://github.com/PotHix/rocketchat-gitlab-hook).

axilleas/gitlabhq,t-zuehlsdorff/gitlabhq,stoplightio/gitlabhq,iiet/iiet-git,t-zuehlsdorff/gitlabhq,LUMC/gitlabhq,mmkassem/gitlabhq,mmkassem/gitlabhq,stoplightio/gitlabhq,stoplightio/gitlabhq,openwide-java/gitlabhq,jirutka/gitlabhq,dplarson/gitlabhq,jirutka/gitlabhq,darkrasid/gitlabhq,LUMC/gitlabhq,dreampet/gitlab,mmkassem/gitlabhq,dplarson/gitlabhq,htve/GitlabForChinese,iiet/iiet-git,openwide-java/gitlabhq,LUMC/gitlabhq,darkrasid/gitlabhq,axilleas/gitlabhq,LUMC/gitlabhq,htve/GitlabForChinese,openwide-java/gitlabhq,openwide-java/gitlabhq,axilleas/gitlabhq,stoplightio/gitlabhq,t-zuehlsdorff/gitlabhq,darkrasid/gitlabhq,dreampet/gitlab,jirutka/gitlabhq,t-zuehlsdorff/gitlabhq,htve/GitlabForChinese,iiet/iiet-git,dreampet/gitlab,darkrasid/gitlabhq,dplarson/gitlabhq,htve/GitlabForChinese,dplarson/gitlabhq,iiet/iiet-git,axilleas/gitlabhq,jirutka/gitlabhq,dreampet/gitlab,mmkassem/gitlabhq