Ability to remember last known good build

I participate in an open source project that any pull merge is accepted, no matter what.

This makes for lots of broken builds, even though we do have Travis-CI enabled on the project, because people will merge a request before even the build is complete.

Therefore, I would like to remember the id of the commit of the last successful build. This would be updated by the Travis-CI script itself upon a successful build.

I imagine best option would be to merge master to a certain branch named "Last_known_Linux_build" or "Last_known_Windows_build" or even "Last_known_build_all_tests_passing".

I am new to git, but some other experienced co-volunteers tell me that it may not be possible due to authentication issues.

Any better way of accomplishing this?

Appreciate any comments, Osiris Pedroso