Hey Warren, as many people above said, no need to stop sport.
Actually sport is one reason that keeps me in remission, so I work out 5-6 times a week, go running etc.
In any event, you have probably heard that by now, Crohn's unfortunately a chronic condition which doesn't go away. As you have only been diagnosed a few weeks ago, my advise would be to over the next weeks and months read up on Crohn's, the medical treatments, the studies, the diets, the deficiencies, etc. to really know what it is about. You cannot just rely on your doctor treating it and you cannot rely on medication alone either. Crohn's needs to be tackled on various fronts and principally by you personally.