Slowly-Roasted Turkish Chicken with Vegetables (Köylü Kebab)

1 whole chicken around 1.5 kg (3.3 lb).

1 red bell pepper.

1 green bell pepper.

2 large onions.

1 ½ kg ( 3.3 lb) potatoes peeled.

2-3 medium tomatoes.

Juice of two lemons.

3-4 garlic cloves crushed.

1½ tablespoon tomato paste.

1 cup extra virgin olive oil.

1 tablespoon dried oregano.

Salt and ground pepper.