replace i18n_scope attr_reader/attr_writer with attr_accessor

Author: thambley

lib/active_admin/xls/builder.rb

@@ -100,18 +100,14 @@ def skip_header
         @skip_header = true
       end
 
-      # The scope to use when looking up column names to generate the
-      # report header
-      attr_reader :i18n_scope
-
       # The I18n scope that will be used when looking up your
       # column names in the current I18n locale.
       # If you set it to [:active_admin, :resources, :posts] the
       # serializer will render the value at active_admin.resources.posts.title
       # in the current translations
       #
       # @note If you do not set this, the column name will be titleized.
-      attr_writer :i18n_scope
+      attr_accessor :i18n_scope
 
       # The stored block that will be executed after your report is generated.
       #