FIX: uses compiler version to force rebaking of themes (#6870)

Co-Authored-By: David Taylor <david@taylorhq.com>

app/models/theme_field.rb

@@ -39,7 +39,7 @@ class ThemeField < ActiveRecord::Base
   validates :name, format: { with: /\A[a-z_][a-z0-9_-]*\z/i },
                    if: Proc.new { |field| ThemeField.theme_var_type_ids.include?(field.type_id) }
 
-  COMPILER_VERSION = 5
+  COMPILER_VERSION = 6
 
   belongs_to :theme
 

db/migrate/20181218143317_force_theme_compilation_for_ember3.rb

@@ -1,6 +0,0 @@
-class ForceThemeCompilationForEmber3 < ActiveRecord::Migration[5.2]
-  def up
-    ThemeField.force_recompilation!
-    Theme.expire_site_cache!
-  end
-end