Merge pull request #1 from thomasrossetto/feat/add_external_id_in_topic_creation

Add support for external_id in topic creation

Author: thomasrossetto

lib/discourse_api/api/topics.rb

@@ -11,7 +11,7 @@ def create_topic(args = {})
           API
             .params(args)
             .required(:title, :raw)
-            .optional(:skip_validations, :category, :auto_track, :created_at, :api_username, :tags)
+            .optional(:skip_validations, :category, :auto_track, :created_at, :api_username, :tags, :external_id)
         post("/posts", args.to_h)
       end