Merge pull request #615 from watson-developer-cloud/nlu-models-patch

fix(NaturalLanguageUnderstanding): add Model param back to CategoriesOptions

Author: mamoonraja

Scripts/Services/NaturalLanguageUnderstanding/V1/Model/CategoriesOptions.cs

@@ -37,5 +37,18 @@ public class CategoriesOptions
         /// </summary>
         [JsonProperty("limit", NullValueHandling = NullValueHandling.Ignore)]
         public long? Limit { get; set; }
+        /// <summary>
+        /// Enter a [custom
+        /// model](https://cloud.ibm.com/docs/services/natural-language-understanding?topic=natural-language-understanding-customizing)
+        /// ID to override the standard categories model
+        ///
+        /// **Deprecated**
+        // The custom categories experimental feature will be retired on 19 December 2019. On that date, deployed custom
+        // categories models will no longer be accessible in Natural Language Understanding. The feature will be removed from
+        // Knowledge Studio on an earlier date. Custom categories models will no longer be accessible in Knowledge Studio on 17
+        // December 2019.
+        /// </summary>
+        [JsonProperty("model", NullValueHandling = NullValueHandling.Ignore)]
+        public string Model { get; set; }
     }
 }