MerchantCategoryModel fix 3

@@ -128,7 +128,7 @@ public class MerchantCategoryModel: NSObject {
     
     
     /// Check if this category has child categories
     /// Check if this category has child categories
     public var hasChildren: Bool {
     public var hasChildren: Bool {
-        return !self.children.isEmpty
+        return !(self.children ?? []).isEmpty
     }
     }
 }
 }