added conceal doc

readme.md

@@ -15,6 +15,7 @@ This library was build with webpack in mind but should work well with the other
  * [@inject](#d_inject)
  * [@autobind](#d_autobind)
  * [@attach](#d_attach)
+ * [@conceal](#d_conceal)
 * [Components](#components):
  * [@controller](#d_controller)
  * [@service](#d_service)
@@ -189,6 +190,40 @@ export default class CommunicationService {
 }
 ````
 
+###<a name="d_conceal">`@conceal`<a>
+> declares the annotated property as private
+
+#### type: *statement*
+#### target: *methods and attributes*
+#### Usage:
+````javascript
+import {factory, inject, attach, conceal} from 'node_modules/ng-annotations';
+
+@factory()
+@inject('$http')
+export default class UserFactory {
+
+ @conceal
+ @attach('$http')
+ $http
+
+ @conceal
+ datas = [];
+
+ constructor(timeout) {
+ this.datas = [1,2,3];
+ }
+
+ method() {
+ return this.privateMethod();
+ }
+
+ @conceal
+ privateMethod() {}
+}
+````
+
+
 ###<a name="d_autobind">`@autobind`<a>
 > The autobind annotation gives the possibility to bind methods to its current context. 
 > similar to *object.method.bind(object)*