What foods contain vitamin d ?!

Most foods don't contain significant amounts of vitamin D, and the ones that are fortified are usually done with D2 and not D3 which is what you need. Vitamin D3 supplements are super cheap. The daily recommendation is 5,000 to 10,000 iu based on the most recent studies. The RDA is so low it's a joke. Anyone who lives north of Atlanta cannot make any vitamin D in the winter at all.
There's good info. at Mercola.com. (you can also research natural treatments for psoriasis too).

The old fashion remdy was cod liver oil. But psoriasis is too serious. Even prescriptions do little. I have found that rubbing sulfur powder on scalp at night with a soft hat is the only remedy that works. Avoid gtting any in the eyes as it will sting them.

Increase your intake of sunlight, so go outside more often, and eat more eggs, oily fish, breakfast cereals, powdered milk, liver etc.

milk,yogurt,cheese,spinach