One of the preferred exercises is swimming since it involves all muscles and joints in a low-impact, buoyant environment.
Its not so much as controlling the disease as learning to live with it. I was diagnosed at aged 20 and being female did not fit the usual profile for the illness. In the beginning it was very tough, I had to give up work and was in a lot of pain for a long time. However I learnt that the most important thing is to keep active. In the beginning my Rheumatologist referred me for physiotherapy and I joint an exercise class with people suffering from the same or similar illnesses. Once you learn which exercises you can safely do then you should do them often - I did them every day at first but now I just go to the gym every other day and do gentle stretching exercises and some walking on the treadmill. There are times when I have a "flare up" and this is painful. I just wake up one morning unable to move without pain and I know that time has come. All I can do is take anti-inflammatories, painkillers and get moving - no matter how much it hurts at this stage exercises are a MUST. I also find that a hot water bottle can soothe the pain at night.
Sorry if you were hoping for something more positive but this is really all there is. The main thing is that you CAN live with this - if you take care of yourself then there is no reason why you can't live a fairly normal life. Good luck