Vegetable Soup

Ingredients
For the Soup:

1 onion, chopped
Olive oil
2 leeks, chopped
2 stalks of celery, chopped
1 carrot, diced
1 red pepper, diced
1 zucchini, diced
2 potatoes, diced
2 garlic cloves, minced
1 chili pepper, minced (optional, for spice)