created optimized_image model

app/models/optimized_image.rb

@@ -0,0 +1,7 @@
+class OptimizedImage < ActiveRecord::Base
+  belongs_to :upload
+
+  def filename
+    "#{sha[0..2]}/#{sha[3..5]}/#{sha[6..16]}_#{width}x#{height}#{ext}"
+  end
+end

app/models/upload.rb

@@ -9,6 +9,8 @@ class Upload < ActiveRecord::Base
   has_many :post_uploads
   has_many :posts, through: :post_uploads
 
+  has_many :optimized_images
+
   validates_presence_of :filesize
   validates_presence_of :original_filename