Fixed issue with has_top_container (#6)

* Fixed issue with `has_top_container`

`has_top_container` was always evaluating to false. This logic was possibly broken by new releases of ArchivesSpace.

* Update Readme.md

New release documentation

* Update Readme.md

Grammar change, to keep with style and phrasing of other entries in the changelog

Readme.md

@@ -69,7 +69,8 @@ of ArchivesSpace may cause changes in the functionality of this plugin.
     - Fixed a bug where only the first container would be included in the request.
     - Markup is now stripped from the `title` parameter.
     - Plugin has been refactored so builtin ArchivesSpace functionality can be used.
-
+- **20180410**
+    - Fixed a bug with the `:requests_permitted_for_containers_only` setting
 
 ## Configuring Plugin Settings
 

public/models/record_mapper.rb

@@ -39,7 +39,7 @@ def show_action?
                 puts "Aeon Fulfillment Plugin -- Checking for top containers"
                 has_top_container = false
 
-                instances = self.record.dig('json', 'instances')
+                instances = self.record.json['instances']
                 if instances
                     instances.each do |instance|