Hello and welcome to the crohns forum
.
I've been diabetic for 17years (type1) and was diagnosed 9 months ago with crohns, I can understand how confused you will be feeling right now cos I was utterly overwhelmed. The diet regimes to help both are quite different, I would suggest that you have a look at the low residue diet info on the forum wiki as to what you should avoid, basically it means that you have to reduce the fibre you eat and avoid spicy foods, caffeine, alcohol, corn and corn products, nuts and whole grains, foods with skins on, carbonated drinks and I can't remember the rest.
This is a list o foods my dietician said were safe safe for me to eat. Malted drinks and milky drinks. White bread, plain scones and pancakes. While pastas and rice. All pudding cereals, eg. rice, tapioca, sack, semolina, custard powder and Cornelius. Rice krispies, porridge and corn flakes. Eggs, cheese, milk, plain yoghurt, cream and butter. Sugar free jellies, plain sponge puddings, milk puddings and all milk based desserts. 1portion of a safe fruit and the same of veg. Potatoes without skins. All lean meat meat and poultry. Clear or strained soups. Seedless jams and seedless marmalade (although teaspoon size portion).
Hope this helps, feel free to message me if you want a chat. Good luck.