add check for git status

Makefile

@@ -1,16 +1,20 @@
-city_distances.csv: lint generate_data.py
+city_distances.csv: check generate_data.py
 	bash -c 'time python generate_data.py'
 
+train: check train.py
+	bash -c 'time python train.py'
+
+eval: check eval.py
+	bash -c 'time python eval.py'
+
 lint:
 	isort --profile=black .
 	black .
 	flake8 --max-line-length=88 .
 
-train: lint train.py
-	bash -c 'time python train.py'
-
-eval: lint eval.py
-	bash -c 'time python eval.py'
+check: lint
+	@echo "Checking for unstaged or untracked changes..."
+	@git diff-index --quiet HEAD -- || { echo "Unstaged or untracked changes detected!"; exit 1; }
 
 clean:
 	rm -rf output/