Melt butter in a large, heavy saucepan over medium high heat. Place bacon in the saucepan, and cook until evenly brown. Stir in onion and celery, and cook until tender. Mix in tomato, tomato puree and ketchup. Season with salt and pepper. Reduce heat to low, and continue cooking about 15 minutes.
Stir gungo peas and their liquid, water, rice and thyme into the saucepan. Bring to the boil, cover, and reduce heat. Cook 40 minutes on low, or until all liquid is absorbed. Fluff rice with a fork.
You can find tinned gungo peas at Caribbean or Asian shops, as well as online. If in a pinch, dried will work so long as you've soaked and boiled them first. Otherwise, try using a tin of black eyed beans instead.
Gungo peas are also known as pigeon peas, toor dal and Congo peas.