Courtney's BBQ Sloppy Joes

1 lb ground beef
1 onion (1/4 cup chopped)
1-2 Celery Stalks
1 tsp salt
1 dash pepper
1 cup ketchup
1/4 cup water
1/4 cup brown sugar
2 tsp vinegar
1 tsp mustard

brown meat and onion. add salt and pepper, then mix in the rest.