Pushing to different repo for github pages fails on push

I’d think I configured everything correctly, but still I can not get travis to push to my docs repo for the generated docs, here is the build: https://travis-ci.org/ArSn/jay-gee-eff-for-web/builds/513454883

What I did do so far:

  1. Double check the personal access token - I even regenerated it
  2. Switched between email/name and committer_from_gh configs, which did not seem to have any effect
  3. Enabled the verbose output, but it did not get very much more verbose about the failed push

I noticed that it says
Installing deploy dependencies
invalid options: -SHN
(invalid options are ignored)

earlier, but since I am not passing any single character options here I am not sure what I am doing wrong, I went along these docs: https://docs.travis-ci.com/user/deployment/pages/#further-configuration

As it turns out I just did not notice I should include the username in the repo slug, therefore I created this PR to extend the docs: https://github.com/travis-ci/docs-travis-ci-com/pull/2331