Add ability to use nested only parameter

- The only string works much the same as before with its comma separation
-- Nested includes are indicated with square brackets "[ ]"
-- The nested include is the value immediately preceding the square brackets
-- The only string is the comma separated string inside those brackets
- Default includes are split between format types when necessary
-- This prevents unnecessary includes from being added on page load
- Available includes are those items which are allowed to be accessible to the user
-- Some aren't because they are sensitive, such as the creator of a flag
-- Some aren't because the number of associated items is too large
- The amount of times the same model can be included to prevent recursions
-- One exception is the root model may include the same model once
--- e.g. the user model can include the inviter which is also the user model
-- Another exception is if the include is a has_many association
--- e.g. artist urls can include the artist, and then artist urls again

app/controllers/notes_controller.rb

@@ -6,8 +6,7 @@ class NotesController < ApplicationController
   end
 
   def index
-    @notes = Note.includes(:creator).paginated_search(params)
-    @notes = @notes.includes(:creator) if request.format.html?
+    @notes = Note.paginated_search(params).includes(model_includes(params))
     respond_with(@notes)
   end
 
@@ -60,6 +59,14 @@ class NotesController < ApplicationController
 
   private
 
+  def default_includes(params)
+    if ["json", "xml"].include?(params[:format])
+      [:creator]
+    else
+      [:creator, :post]
+    end
+  end
+
   def note_params(context)
     permitted_params = %i[x y width height body]
     permitted_params += %i[post_id html_id] if context == :create