Marinated Cucumbers, Tomatoes, Green Pepper, and Onion

2 large roma tomatoes
1 cucumber
½ red onion
1 green pepper
1/3 c vinegar
2 tbsp sugar
½ tsp celery seed

Thinly slice tomatoes, cucumber, green pepper and onion. Place in bowl. Mix together vinegar, sugar, and celery seed. Pour over vegetable mixture and stir to coat. Cover bowl and place in refrigerator to chill. Stir occasionally.