post disapprovals: fix tests and API create action.

* Fix tests.
* Fix create action in API (couldn't redirect to show action).
* Clean up user initialization.

config/routes.rb

@@ -205,7 +205,7 @@ Rails.application.routes.draw do
   resources :post_appeals
   resources :post_flags
   resources :post_approvals, only: [:index]
-  resources :post_disapprovals, only: [:create, :index]
+  resources :post_disapprovals, only: [:create, :show, :index]
   resources :post_versions, :only => [:index, :search] do
     member do
       put :undo