Added code to prevent error while committing with no changes

[gautamkrishnar]

As of now if someone is using the example code from the readme and they don't have any local changes, the workflow will fail with an error. It's better to prevent this in the example code itself. Added code to prevent error while committing with no changes, This will check whether the Head has changed and will execute the commit command only if it changed. It will prevent the following error:

> git commit -m "hello"           
On branch master
Your branch is up to date with 'origin/master'.

nothing to commit, working tree clean
> echo $?
1

Git commit command returns a non zero exit status if there's no change

Solution

git diff-index --quiet HEAD will return non zero status only if there's a change added via git add this will jump into the || or condition and executes the git commit command. If git diff-index --quiet HEAD returns zero (when there's no change), the git commit command will not be executed, hence it will prevent the error code from getting thrown.