It's kind of hit-or-miss as to what bothers individuals, but fish is usually well tolerated, especially salmon. I find avocado works well when I am in a bad flare. Eggs are also a good source of protein. Avoid fibrous foods, seeds, gassy vegs, such as brocolli, peppers and onions. Green beans tend to be okay for many people. Sushi is good as well, believe or or not.
If you're on Prednisone make sure you get plenty of calcium, use supplements if you can't tolerate dairy, but yogurt is good, the its probiotics are very beneficial. I find Viactive cheese with probiotics is a good source of protein and calcium.
You also need to watch your Potassium when on Pred, so try to eat a banana or two every day.