Add simple prediction comparison

src/routes/prediction.ts

@@ -16,5 +16,11 @@ router.post('/prediction/new', (req, res, next) => {
 	});
 });
 
+router.post('/prediction/compare', async (req, res, next) => {
+	const valA = (await PredictionModel.findOne({ name: req.body.nameA })).value;
+	const valB = (await PredictionModel.findOne({ name: req.body.nameB })).value;
+	res.json(valB - valA);
+});
+
 
 module.exports = router;