development environment - Managing a git repository across multiple websites -

my coding in past has been casual--i grab project github (or wherever) , implement on website if liked , manually tweak if needed or wanted to, making note of changes made in case ever needed reinstall. i'm getting deeper development, however, , have github repository develop on windows 8.1 machine , implement on 3 different "live" testing, non-critical environments each require different custom setup.

i've never used git in way before 1 live environment, let alone three. there automated way handle git, or have stick .gitignore , manually apply settings ignored files? question mention github because that's i'm using, generalized answer still gets @ premise of question acceptable.

if issue want each machine read different configurations, set config file determine system on , have load corresponding settings.

alternatively, if not have change structure of config files, put them in include path outside git repo.