Claypot Chicken

Ingredients:
1 tablespoon olive oil, 1 onion, peeled and chopped, 1 thumb ginger, peeled and finely chopped, 1 clove garlic, peeled and chopped, 4 chicken thigh fillets, each cut into 6 pieces, 1 tablespoon brown sugar, 4 tablespoons basmati rice, 1 tablespoon fish sauce, 250ml chicken stock