#434

backend/app/models/post_version.rb

@@ -1,6 +1,11 @@
 class PostVersion < ApplicationRecord
   include VersionRecord
 
+  scope :with_previous_version, -> {
+    joins('LEFT JOIN post_versions prev ON prev.post_id = post_versions.post_id ' +
+          'AND prev.version_no = post_versions.version_no - 1')
+  }
+
   belongs_to :post
   belongs_to :parent, class_name: 'Post', optional: true