Simple flow for creating categories

- Also includes a dev-facing index for removing them (for now)
- Saves an interim bubble style for posterity

config/routes.rb

@@ -1,8 +1,12 @@
 Rails.application.routes.draw do
   root "splats#index"
 
+  resources :categories, only: %i[index destroy]
   resource :session
-  resources :splats
+
+  resources :splats do
+    resources :categories, only: %i[new create]
+  end
 
   get "up" => "rails/health#show", as: :rails_health_check
 end