Improve JSON output for media attachments, generate :small preview for them

app/models/media_attachment.rb

@@ -2,7 +2,7 @@ class MediaAttachment < ApplicationRecord
   belongs_to :account, inverse_of: :media_attachments
   belongs_to :status,  inverse_of: :media_attachments
 
-  has_attached_file :file
+  has_attached_file :file, styles: { small: '510x680>' }
   validates_attachment_content_type :file, content_type: /\Aimage\/.*\z/
 
   validates :account, presence: true

app/views/api/statuses/show.rabl

@@ -17,6 +17,9 @@ child :account do
   extends('api/accounts/show')
 end
 
-child :media_attachments do
+child :media_attachments, object_root: false do
+  attribute :remote_url
+
   node(:url) { |media| full_asset_url(media.file.url) }
+  node(:preview_url) { |media| full_asset_url(media.file.url(:small)) }
 end