push.sh: nicely exit if nothing to push

push.sh

@@ -10,13 +10,17 @@ git config --global user.name "veggiemonk-bot"
 # let git know where to apply the changes
 git checkout master
 
-echo 'Adding data files'
+echo "Adding data files"
 git add data/*
 
-echo 'Commiting files'
-git commit -m 'Automated update repository metadata [skip ci]'
+echo "Checking the number of files staged"
+files=$(git diff --cached --numstat | wc -l | tr -d '[:space:]');
+[[ $files -eq 0 ]] && echo "nothing to push, exiting..." && exit
 
-echo 'Pushing changes'
+echo "Commiting files"
+git commit -m "Automated update repository metadata [skip ci]"
+
+echo "Pushing changes"
 git push https://$GITHUB_USER:$GITHUB_TOKEN@github.com/veggiemonk/awesome-docker master >/dev/null 2>&1
 
-echo 'Done.'
+echo "Done."