Rename the hidden option to whitelisted

app/models/broadcast_message.rb

@@ -4,7 +4,7 @@ class BroadcastMessage < ActiveRecord::Base
   include CacheMarkdownField
   include Sortable
-  cache_markdown_field :message, pipeline: :broadcast_message, hidden: false
+  cache_markdown_field :message, pipeline: :broadcast_message, whitelisted: true
   validates :message,   presence: true
   validates :starts_at, presence: true

app/models/concerns/cache_markdown_field.rb

@@ -7,7 +7,7 @@
 #     cache_markdown_field :foo
 #     cache_markdown_field :bar
 #     cache_markdown_field :baz, pipeline: :single_line
-#     cache_markdown_field :baz, hidden: false
+#     cache_markdown_field :baz, whitelisted: true
 #
 # Corresponding foo_html, bar_html and baz_html fields should exist.
 module CacheMarkdownField
@@ -41,9 +41,9 @@ module CacheMarkdownField
       markdown_fields.map { |field| html_field(field) }
     end
-    def hidden_html_fields
+    def html_fields_whitelisted
       markdown_fields.each_with_object([]) do |field, fields|
-        if @data[field].fetch(:hidden, true)
+        if @data[field].fetch(:whitelisted, false)
           fields << html_field(field)
         end
       end
@@ -159,13 +159,14 @@ module CacheMarkdownField
     def attributes
       attrs = attributes_before_markdown_cache
       html_fields = cached_markdown_fields.html_fields
-      hidden_html_fields = cached_markdown_fields.hidden_html_fields
-      hidden_html_fields.each do |field|
+      whitelisted = cached_markdown_fields.html_fields_whitelisted
+      exclude_fields = html_fields - whitelisted
+      exclude_fields.each do |field|
         attrs.delete(field)
       end
-      if (html_fields - hidden_html_fields).empty?
+      if whitelisted.empty?
         attrs.delete('cached_markdown_version')
       end

spec/models/concerns/cache_markdown_field_spec.rb

@@ -23,7 +23,7 @@ describe CacheMarkdownField do
     include CacheMarkdownField
     cache_markdown_field :foo
     cache_markdown_field :baz, pipeline: :single_line
-    cache_markdown_field :zoo, hidden: false
+    cache_markdown_field :zoo, whitelisted: true
     def self.add_attr(name)
       self.attribute_names += [name]
@@ -85,7 +85,7 @@ describe CacheMarkdownField do
   end
   describe '.attributes' do
-    it 'excludes cache attributes that is hidden by default' do
+    it 'excludes cache attributes that is blacklisted by default' do
       expect(thing.attributes.keys.sort).to eq(%w[bar baz cached_markdown_version foo zoo zoo_html])
     end
   end