Update api URL (#185)

This change updates the production API URL to https://api.granblue.team/v1 instead of https://api.granblue.team/api/v1.

config/routes.rb

@@ -4,8 +4,9 @@ Rails.application.routes.draw do
     skip_controllers :applications, :authorized_applications
   end
 
-  namespace :api, defaults: { format: :json } do
-    namespace :v1 do
+  path_prefix = Rails.env.production? ? '/v1' : '/api/v1'
+
+  scope path: path_prefix, module: 'api/v1', defaults: { format: :json } do
     resources :parties, only: %i[index create update destroy]
     resources :users, only: %i[create update show]
     resources :grid_weapons, only: %i[update destroy]
@@ -74,7 +75,6 @@ Rails.application.routes.draw do
 
     delete 'favorites', to: 'favorites#destroy'
   end
-  end
 
   if Rails.env.development?
     get '/party-previews/*filename', to: proc { |env|