fix compile error

Sources/App/Controllers/StatsController.swift

@@ -155,7 +155,7 @@ struct StatsController: RouteCollection {
         
         
         return Match.query(on: req.db).filter(\.$date > startDate!).all().map { (matches) -> (Stats) in
-           return getStats(matches: matches)
+            return self.getStats(matches: matches)
         }
     }