README.md in store_model-0.5.1 vs README.md in store_model-0.5.2

@@ -87,9 +87,10 @@
   * [Enums](./docs/enums.md)
   * [Nested models](./docs/nested_models.md)
   * [Unknown attributes](./docs/unknown_attributes.md)
 3. [Array of stored models](./docs/array_of_stored_models.md)
 4. [Alternatives](./docs/alternatives.md)
+5. [Defining custom types](./docs/defining_custom_types.md)
 
 ## License
 
 The gem is available as open source under the terms of the [MIT License](https://opensource.org/licenses/MIT).