https://stackoverflow.com/a/11183844

Since this is a case sensitive rename and we don't want to end up with a commit saying we removed a couple of files and added new files into another folder we have to make sure our git commit understands what happened.
Should work by standing in the right folder and doing the following:

git mv fileHandler tmp
git mv tmp filehandler

Before commiting make sure that git status shows it as a rename.