Add markdown cache columns to the database, but don't use them yet

This commit adds a number of _html columns and, with the exception of Note,
starts updating them whenever the content of their partner fields changes.

Note has a collision with the note_html attr_accessor; that will be fixed later

A background worker for clearing these cache columns is also introduced - use
`rake cache:clear` to set it off. You can clear the database or Redis caches
separately by running `rake cache:clear:db` or `rake cache:clear:redis`,
respectively.

1 files changed, 5 insertions, 0 deletions

diff --git a/app/models/global_milestone.rb b/app/models/global_milestone.rb
index bda2b5c5d5d..cde4a568577 100644
--- a/app/models/global_milestone.rb
+++ b/app/models/global_milestone.rb
@@ -4,6 +4,10 @@ class GlobalMilestone
   attr_accessor :title, :milestones
   alias_attribute :name, :title
 
+  def for_display
+    @first_milestone
+  end
+
   def self.build_collection(milestones)
     milestones = milestones.group_by(&:title)
 
@@ -17,6 +21,7 @@ class GlobalMilestone
     @title = title
     @name = title
     @milestones = milestones
+    @first_milestone = milestones.find {|m| m.description.present? } || milestones.first
   end
 
   def safe_title