Add @Strong flag

src/decorators/index.ts

@@ -1,3 +1,4 @@
 export * from './exclude';
 export * from './memoize';
-export * from './pluck';
+export * from './pluck';
+export * from './strong';

src/decorators/strong.ts

@@ -0,0 +1,9 @@
+export const STRONG_CLASS_KEY = 'serde:strong_class';
+
+export function Strong(): Function {
+    return function(target: any) {
+        if (!Reflect.hasMetadata(STRONG_CLASS_KEY, target)) {
+            Reflect.defineMetadata(STRONG_CLASS_KEY, 'is_strong_typed', target);
+        }
+    }
+}