Clean up route configuration

* Avoid old ruby hash syntax;
* Sort rules;
* Refactor arguments to :only options.

config/routes.rb

@@ -2,25 +2,24 @@ Rails.application.routes.draw do
   root 'home#index'
 
   namespace :api do
-    get '/ping' => 'application#ping'
-    resources :sounds, only: [:show]
-    resources :tracks, only: [:index]
-    resources :playlists, only: [:index, :create]
-    resources :sessions, only: [:create]
-
-    match '*all' => 'application#cor_preflight', via: :options
+    get '/ping', to: 'application#ping'
+    match '*all', to: 'application#cor_preflight', via: :options
+    resources :playlists, only: %i[index create]
+    resources :sessions, only: :create
+    resources :sounds, only: :show
+    resources :tracks, only: :index
   end
 
-  resources :sounds, only: [:show]
+  resources :playlists
 
-  resources :users, only: [:new, :create]
+  resources :sessions, only: %i[new create]
+  get '/signout', to: 'sessions#destroy'
 
-  resources :sessions, only: [:new, :create]
-  get '/signout' => 'sessions#destroy'
+  resources :sounds, only: :show
 
   resources :tracks do
     get 'download', on: :member
   end
 
-  resources :playlists
+  resources :users, only: %i[new create]
 end