I'm still fairly new to using Git and GitHub. I've taken the Code School courses on Git, but my actual working knowledge is limited. Today I broke this website because my Production server is set to allow Node applications to run on Port 80, but my development server was not. I didn't realize that of course. All I knew is that I broke the build between commits.
I followed the directions on this GitHub tutorial and was able to revert a commit and figure out exactly what I did to break the build.
I also found this great little tidbit for overwriting troublesome files that aren't allow ing me to revert or commit:
git checkout HEAD^ file/to/overwrite
git pull