Fix typo and change URL of custom hooks doc in main README (!542) · Merge requests · GitLab.org / GitLab · GitLab

Achilleas Pipinellis - OOO until November 25th (parental leave) requested to merge doc-custom-hook into master Jul 09, 2016

Partially includes https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/5169