Update git hook script

Made the git hook script more expressive.
Signed-off-by: Taico Aerts <t.v.aerts@tudelft.nl>

contributing/hooks/setup_commit_msg_hook.sh

@@ -2,11 +2,19 @@
 #
 # Put this script inside the root folder of your git directory before running it.
 
-cat >.git/hooks/commit-msg <<'EOF'
+if cat >.git/hooks/commit-msg<<'EOF'
 #!/bin/sh
 grep "^Signed-off-by:" "$1" || {
 	echo >>"$1"
 	echo "Signed-off-by: $(git config user.name) <$(git config user.email)>" >>"$1"
 }
 EOF
-chmod +x .git/hooks/commit-msg
\ No newline at end of file
+then
+	chmod +x .git/hooks/commit-msg || {
+		echo "Installation failed: failed to adjust permissions"
+		exit 1
+	}
+	echo "Installed git commit hook successfully"
+else
+	echo "Installation failed: could not write the commit hook"
+fi